Directory of Researchers

UCHIYAMA Yusuke
Graduate School of Engineering / Department of Civil Engineering
Professor
Civil Engineering / Architecutre and planning / Building Engineering
Last Updated :2022/09/26

Researcher Profile and Settings

Affiliation

  • <Faculty / Graduate School / Others>

    Graduate School of Engineering / Department of Civil Engineering
  • <Related Faculty / Graduate School / Others>

    Faculty of Engineering / Department of Civil Engineering

Teaching

Research Activities

Research Interests

  • Ocean Modeling
  • Physical Oceanography
  • Coastal Engineering

Research Areas

  • Natural sciences / Atmospheric and hydrospheric science / Oceanography
  • Social infrastructure (civil Engineering, architecture, disaster prevention) / Hydroengineering

Awards

  • Oct. 2021 The 4th International Symposium on Green and Sustainable Technology, Best Presenter Award, Generation Mechanism of Tidally-driven Whirlpools at a Narrow Strait in an Estuary

    Uchiyama, Y.

  • May 2021 土木学会, 令和2年度土木学会賞・国際活動奨励賞

    内山雄介

  • Oct. 2020 神戸大学工学部, 令和元年度優秀教育賞

    内山雄介

  • Oct. 2018 Elsevier, Outstanding Contribution in Reviewing Award 2018, Ocean Modelling

    Uchiyama, Y.

  • Oct. 2018 Elsevier, Outstanding Contribution in Reviewing Award 2018, Progress in Oceanography

    Uchiyama, Y.

  • Jul. 2018 Elsevier, Outstanding Contribution in Reviewing Award 2018, Deep-Sea Research Part I

    Uchiyama, Y.

  • Oct. 2017 神戸大学, 平成29年度学長表彰

    内山雄介

  • Sep. 2016 神戸大学工学部, 平成27年度優秀教育賞

    内山雄介

  • Nov. 2015 Elsevier, Outstanding Contribution in Reviewing Award 2015, Continental Shelf Research

    Uchiyama, Y.

  • Oct. 2015 神戸大学工学部, 平成26年度優秀教育賞

    内山雄介

  • Oct. 2014 Elsevier, Outstanding Contribution in Reviewing Award 2014, Ocean Modelling

    Uchiyama, Y.

  • Sep. 2014 神戸大学工学部, 平成25年度優秀教育賞

    内山雄介

  • Sep. 2014 IAHR-APD, Best Paper Award 2014, On tridimensional rip current modeling

    Marchesiello, P, Benshila, R, Almar, R, Uchiyama, Y, McWilliams, J, Shchepetkin, A

  • Aug. 2014 公益財団法人クリタ水・環境科学振興財団, 平成26年度クリタ水・環境科学研究優秀賞, 瀬戸内海全域における外洋影響を考慮した広域流動の動態把握と内湾環境保全戦略

    内山雄介

  • Mar. 2014 Elsevier, Most Cited Ocean Modelling Articles, Wave-current interaction in an oceanic circulation model with a vortex force formalism: Application to the surf zone

    Uchiyama, Y, McWilliams, J.C, Shchepetkin, A.F

  • Sep. 2013 神戸大学工学部, 平成24年度優秀教育賞

    内山雄介

Published Papers

  • Yuki Kamidaira, Yusuke Uchiyama, Hideyuki Kawamura, Takuya Kobayashi, Shigeyoshi Otosaka

    Elsevier BV, Nov. 2021, Journal of Environmental Radioactivity, 238-239, 106724 - 106724, English

    [Refereed]

    Scientific journal

  • Yusuke Uchiyama, Natsuki Tokunaga, Kohei Aduma, Yuki Kamidaira, Daisuke Tsumune, Toshiki Iwasaki, Masatoshi Yamada, Yutaka Tadeda, Takashi Ishimaru, Yukari Ito, Yutaka W. Watanabe, Ken Ikehara, Miho Fukuda, Yuichi Onda

    Accidental leakage of radionuclides from the Fukushima Nuclear Power Plant (FNPP1) took place in the aftermath of the catastrophic tsunamis associated with the Great East Japan Earthquake that occurred on March 11, 2011. Significant amount of radionuclides released into the atmosphere were reportedly transported and deposited on land located near FNPP1. The Niida River, Fukushima, Japan, has been recognized as a terrestrial source of highly contaminated suspended radiocesium adhering to sediment particles in the ocean through the river mouth as a result of hydrological processes. Remaining scientific questions include the oceanic dispersal and inventories of the sediments and suspended radiocesium in the ocean floor derived from the Niida River. Complementing limited in situ data, we developed a quadruple nested 3D ocean circulation and sediment transport model in an extremely high-resolution configuration to quantify the transport processes of the suspended radiocesium. Particularly, we investigated the storm and subsequent floods associated with Typhoon 201326 (Wipha) that passed off the Fukushima coast in October 2013, and subsequently promoted precipitation to a considerable extent and associated riverine freshwater discharge along with sediment outfluxes to the ocean. Using in situ bed sediment core data obtained from regions near the river mouth, we conducted a quantitative assessment of the accumulation and erosion of the sediments and explored the resultant suspended radiocesium distribution around the river mouth and nearshore areas along the Fukushima coast. We identified three major accumulative areas, near the river mouth within an area < 1 km, around the breakwaters in the north of the river mouth, and along the southern coastal area, while offshore and northward transports were minor. The present study clearly exhibits substantial retention of the land-derived radiocesium adsorbed to the sediments in the coastal areas, leading to possible long-term influences on the surrounding marine environment.

    Elsevier BV, Nov. 2021, Science of The Total Environment, 816, 151573 - 151573, English, International magazine

    [Refereed]

    Scientific journal

  • Peng Wang, James C. McWilliams, Yusuke Uchiyama

    AbstractCoastal fronts impact cross-shelf exchange of materials, such as plankton and nutrients, which are important to the ecosystems in continental shelves. Here using numerical simulation we demonstrate a nearshore front induced by wave streaming. Wave streaming is a bottom Eulerian current along the surface wave direction, and it is caused by the wave bottom dissipation. Wave streaming drives a Lagrangian overturning circulation in the inner shelf and pumps up deep and cold water into the overturning circulation. The water inside the overturning circulation is quickly mixed and cooled because of the wave streaming-enhanced viscosity. However, the offshore water outside the overturning circulation remains stratified and warmer. Hence, a front develops between the water inside and outside the overturning circulation. The front is unstable and generates submesoscale shelf eddies, which lead the offshore transport across the front. This study presents a new mechanism for coastal frontogenesis.

    American Meteorological Society, 05 Apr. 2021, Journal of Physical Oceanography, English

    [Refereed]

    Scientific journal

  • Naoya Takeda, Motohiko Kashima, Sachika Odani, Yusuke Uchiyama, Yuki Kamidaira, Satoshi Mitarai

    A massive coral bleaching event occurred in 2016 in the interior of Japan's largest coral lagoon, the Sekisei Lagoon, located in the Kuroshio upstream region in southwestern Japan. Recovery of the coral lagoon will require the influx of coral spawn and larvae; therefore, it is important to identify and conserve source sites. A surface-particle-tracking simulation of coral spawn and larvae was used to identify source areas of coral spawn outside of the Sekisei Lagoon for potential recovery of the interior lagoon. The northern coastal zone of Iriomote Island, including Hatoma Island, was identified as a major source area. Hatoma Island was also identified as a key source for the Kuroshio downstream region and for aiding the poleward migration of coral habitat under ongoing global climate change, making it one of the most important source areas in the Nansei Archipelago.

    26 Mar. 2021, Scientific reports, 11 (1), 6963 - 6963, English, International magazine

    [Refereed]

    Scientific journal

  • Kosei MATSUSHITA, Yusuke UCHIYAMA, Naru TAKAURA, Taichi KOSAKO

    Corresponding, Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77 (2), I_1003 - I_1008

    [Refereed]

    Scientific journal

  • Kimika TAKEYASU, Yusuke UCHIYAMA, Xu ZHANG, Kosei MATSUSHITA, Satoshi MITARAI

    Corresponding, Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77 (2), I_883 - I_888

    [Refereed]

    Scientific journal

  • Motoki UBARA, Yusuke UCHIYAMA, Taichi KOSAKO

    Corresponding, Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77 (2), I_169 - I_174

    [Refereed]

    Scientific journal

  • Hongxin WANG, Kenta KUROSAWA, Yusuke UCHIYAMA

    Corresponding, Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77 (2), I_385 - I_390

    [Refereed]

    Scientific journal

  • Takayoshi INOUE, Eiji MASUNAGA, Taichi KOSAKO, Xu ZHANG, Yusuke UCHIYAMA

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77 (2), I_373 - I_378

    [Refereed]

    Scientific journal

  • Masashi IKEDA, Eiji MASUNAGA, Yota SUZUE, Sachihiko ITOH, Yusuke UCHIYAMA

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77 (2), I_379 - I_384

    [Refereed]

    Scientific journal

  • Peng Wang, James C. McWilliams, Yusuke Uchiyama, Mickaël D. Chekroun, Daling Li Yi

    AbstractWave streaming is a near-bottom mean current induced by the bottom drag on surface gravity waves. Wave variations include the variations in wave heights, periods, and directions. Here we use numerical simulations to study the effects of wave streaming and wave variations on the circulation that is driven by incident surface waves. Wave streaming induces an inner-shelf Lagrangian overturning circulation, which links the inner shelf with the surf zone. Wave variations cause alongshore-variable wave breaking that produces surf eddies; however, such eddies can be suppressed by wave streaming. Moreover, with passive tracers we show that wave streaming and wave variations together enhance the cross-shelf material transport.

    American Meteorological Society, 01 Oct. 2020, Journal of Physical Oceanography, 50 (10), 3025 - 3041, English

    [Refereed]

    Scientific journal

  • High wave coniditions due to typhoons measured at an offshore observation tower

    Baba, Y, Kubo, T, Mori, N, Watanabe, Y, Yamada, T, Saruwatari, A, Otsuka, J, Uchiyama, Y, Ninomiya, J, Shimura, T

    Sep. 2020, Proc. 22nd IAHR-APD Congress, 2-4-4 - 2-4-4

    [Refereed]

    International conference proceedings

  • Çiğdem Akan, James C. McWilliams, Yusuke Uchiyama

    © 2020 Rip currents arise from the momentum flux associated with depth-induced breaking of incident surface gravity waves on beaches with irregular bottom topography. In 3D simulations with an idealized topographic configuration, uniform density, and a steady incident wave field, a striking enhancement of transient surf eddy variability occurs over irregular topography compared to smooth topography, especially at nearly normal incident wave angles. Alternatively, with highly oblique incident waves, transient shear instability is observed over smooth topography whereas for irregular topography, standing rip eddies are generated. In the presence of larger-scale coastline variations, mega-rip circulations emerge, and they are especially strong for embayments. In all cases with significant transient surf-eddy activity, the eddy-induced mean horizontal transport is a non-trivial component of the total mean transport, and sometimes it is much larger than the gravity-wave Stokes drift. Typically the transport by the eddy-induced flow partially cancels the Eulerian transport by the time- and/or alongshore-averaged currents, but not by enough to reverse the “residual” pattern of total transport.

    Mar. 2020, Ocean Modelling, 147

    [Refereed]

    Scientific journal

  • Kenta Kurosawa, Yusuke Uchiyama, Taichi Kosako

    © 2019 Elsevier Ltd The primary objective of this study is to develop a new weather routing system for vessel navigation in coastal and marginal seas based on the A-star algorithm. The cost function inherent in the original A-star algorithm is modified to account for oceanic and atmospheric conditions around the vessel of interest. Three options are introduced to search for optimal paths with the shortest travel distance, shortest travel time, and minimal fuel consumption. An avoidance algorithm for unsafe conditions is further incorporated to exempt any arbitrary area from the navigation solution. Furthermore, a compact ocean circulation model based on the Regional Ocean Modeling System executable on typical laptop PCs is configured for a vessel-borne weather routing system; the system is successfully applied to evaluate the optimal vessel paths in the Seto Inland Sea, where high-frequency tidal currents modified by complex topography make it essential to alter the vessel's speed.

    01 Jan. 2020, Ocean Engineering, 195

    [Refereed]

    Scientific journal

  • Kosei MATSUSHITA, Yusuke UCHIYAMA, Naru TAKAURA, Taichi KOSAKO

    Corresponding, Japan Society of Civil Engineers, 2020, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 76 (2), I_979 - I_984

    [Refereed]

    Scientific journal

  • Yusuke UCHIYAMA, Xu ZHANG, Shota YANASE

    Japan Society of Civil Engineers, 2020, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 76 (2), I_97 - I_102

    [Refereed]

    Scientific journal

  • Eiji MASUNAGA, Waku KIMURA, Taichi KOSAKO, Xu ZHANG, Yusuke UCHIYAMA

    Japan Society of Civil Engineers, 2020, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 76 (2), I_91 - I_96

    [Refereed]

    Scientific journal

  • Masashi TAKAGI, Nobuhito MORI, Junichi NINOMIYA, Tomoya SHIMURA, Yusuke UCHIYAMA, Yasuyuki BABA, Hideaki MIZUTANI, Teruhiro KUBO, Yasunori WATANABE, Junichi OTSUKA, Tomohito YAMADA, Ayumi SARUWATARI

    Japan Society of Civil Engineers, Nov. 2019, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 75 (2), I_61 - I_66, Japanese

    [Refereed]

    Scientific journal

  • Ayumi SARUWATARI, Junichi OTSUKA, Yasuyuki BABA, Teruhiro KUBO, Hideaki MIZUTANI, Tomoya SHIMURA, Junichi NINOMIYA, Tomohito YAMADA, Yusuke UCHIYAMA, Nobuhito MORI, Yasunori WATANABE

    Japan Society of Civil Engineers, Nov. 2019, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 75 (2), I_67 - I_72, Japanese

    [Refereed]

    Scientific journal

  • Yasuyuki BABA, Teruhiro KUBO, Nobuhito MORI, Yasunori WATANABE, Tomohito YAMADA, Ayumi SARUWATARI, Junichi OTSUKA, Yusuke UCHIYAMA, Junichi NINOMIYA

    Japan Society of Civil Engineers, Nov. 2019, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 75 (2), I_271 - I_276, Japanese

    [Refereed]

    Scientific journal

  • Eiji Masunaga, Yusuke Uchiyama, Hidekatsu Yamazaki

    AbstractThe Kuroshio and tides significantly influence the oceanic environment off the Japanese mainland and promote mass/heat transport. However, the interaction between the Kuroshio and tides/internal waves has not been examined in previous works. To investigate this phenomenon, the two-dimensional high-resolution nonhydrostatic oceanic Stanford Unstructured Nonhydrostatic Terrain-Following Adaptive Navier–Stokes Simulator (SUNTANS) model was employed. The results show that strong internal tides propagating upstream in the Kuroshio are generated at a near-critical internal Froude number (Fri = 0.91). The upstream internal wave energy flux reaches a magnitude of 12 kW m−1, which is approximately 3 times higher than that of internal waves without the Kuroshio. On the other hand, under supercritical conditions, the Kuroshio suppresses the internal wave energy flux. The interaction of internal tides and the Kuroshio also generates upstream propagating high-frequency internal waves and solitary wave packets. The high-frequency internal waves contribute to the increase in the total internal wave energy flux up to 40% at the near-critical Fri value. The results of this study suggest that the interaction of internal tides and the Kuroshio enhances the upstream propagating internal tides under the specified conditions (Fri ~ 1), which may lead to deep ocean mixing and transport at significant distances from the internal wave generation sites.

    American Meteorological Society, Nov. 2019, Journal of Physical Oceanography, 49 (11), 2917 - 2934, English

    [Refereed]

    Scientific journal

  • Zafarullah Nizamani, Akihiko Nakayama, Yusuke Uchiyama, Tey Kim Hai

    © 2019 Author(s). The importance is given for the efficient design of offshore structures which should include economic and safety concerns. The properties of wind-generated (main) surface waves and currents are recognized to play a vital role during design of offshore structures such as windmills, fixed and floating structures. This study looks into the mechanisms of metocean forces, acting on these structures near the continental shelf region of Malaysia. At present, near offshore Malaysia, there is no real behaviour model available for currents and the interaction between waves and current. The free surface flow and rigid body interaction with structural issues of offshore structures such as fatigue, corrosion, and marine growth are also not researched in this region before. Therefore, current and wave-current models need to be developed using the finite volume method. Physics of these forces need to be determined and their free surface flow motions require the development of a framework. Fluid-structure interaction (FSI) is used to model the interfaces such as air-fluid (free surface) and fluid-structure (rigid-body). A Free-surface/rigid body problem fully coupled finite volume model is a preferred method. Six degree of freedom of motion equations are used to define the rigid body. This paper is based on literature review and the expected results due to the effects of wind on wave and currents and the mechanics of current are highlighted along with the seasonal effects of the current. To deal with the moving rigid body and the fluid domain interface an interface-tracking method is used.

    18 Sep. 2019, AIP Conference Proceedings, 2157

    [Refereed]

    International conference proceedings

  • Yusuke Uchiyama, Naru Takaura, Nobue Okada, Akihiko Nakayama

    © 2019 Author(s). A high-resolution, high-precision downscaling oceanic circulation model for the Southern China Sea (SCS) was developed based on the Regional Oceanic Modeling System (ROMS) at a lateral resolution of 5 km, initialized and forced by the HYbrid Coordinate Ocean Model (HYCOM) global reanalysis product. A multi-year reanalysis was conducted with the HYCOM-ROMS system that properly accounts for wind stress and heat budget at surface, freshwater influences from the atmosphere and major rivers, and tidal variability. Prospective applications of the system include assessments of oceanic dispersal of wastewater, quantification of marine ecosystem network, analyses of micro plastic transport and its coastal accumulation, etc. In prior to applied studies, we extensively investigated the validity and performance of the developed system. We found that it successfully reproduced primary dynamics of the SCS in many aspects such as the transient Kuroshio path in the south of Taiwan prominently affecting the circulation of the northern SCS through the Luzon Strait. The North Equatorial Current (NEC) drifting near Bismarck Archipelago, New Guinea, sporadically intrudes into the Indonesian water and adjacent seas to invoke bifurcating northward and westward currents. This intrusion promotes the northwestward mass transport into the Celebes Sea and further into the Sulu Sea, and then enters the SCS through the Palawan Strait.

    18 Sep. 2019, AIP Conference Proceedings, 2157

    [Refereed]

    International conference proceedings

  • Xu Zhang, Yusuke Uchiyama, Akihiko Nakayama

    © 2019 Author(s). Coastal dispersal of sewage effluent from the Tarumi Sewage Treatment Plant located in Osaka Bay, Japan, was investigated with a quadruple-nested high-resolution ROMS model coupled with a 3-D passive tracer model. The study area is quite famous for seaweed farming in the nation, which has been claimed considerably affected by the effluent from the plant, particularly in fall when the seaweed spores are most vulnerable to contamination that counteracts their favorable growth and productivity. We applied the model to three different discharge scenarios to explore possible optimal operations that could reduce the influences. If the discharged volume rate is simply decreased at ∼16.7% relative to the baseline case that represents the actual operation, the effluent accumulating in the farm is reduced at ∼25.4% showing a significant nonlinearity. A tracer flux analysis demonstrated that the transient component accounting for fluctuating tides and eddies dominates over the time-averaged linear contribution to the effluent accumulation in the cross-shore effluent transport to the farm. By contrast, in the along-shore direction, the linear component leads to increased influx near the surface at the western transect of the farm, while the transient component is more essential to the overall reduction of the incoming tracer flux to the farm. On the other hand, density adjustment of the effluent for suppressing surfacing of buoyant effluent plume released from the bottom-mounted diffusers does not work well as expected, because pronounced far-field dilution takes over the near-source dilution affected by the density adjustment.

    Corresponding, 18 Sep. 2019, AIP Conference Proceedings, 2157

    [Refereed]

    International conference proceedings

  • Yusuke Uchiyama, Natsuki Tokunaga

    © 2019 Author(s). Niida River, Fukushima, Japan, is well known to be a source of highly contaminated suspended radiocesium to the ocean, which is originated from the Fukushima Dai-ichi Nuclear Power Plant during the accidental leakage occurred in March 2011. We examined the oceanic dispersal and inventories of the sediments and suspended radiocesium in the ocean floor derived from Niida River, using a quadruple nested JCOPE2-ROMS 3D circulation model in a very high resolution configuration, coupled with a 3D multi-class sediment transport model, the iRIC-Nays 2DH river sediment model, the SWAN spectral wave model, and a static radiocesium absorption model. A particular attention was paid to the storm and subsequent flood event associated with Typhoon 201326 (Wipha) passed off the Fukushima Coast in October 2013, which provoked an enormous amount of precipitation, and subsequent riverine freshwater discharge and sediment fluxes to the ocean. With a guide of several in situ observed data, we carried out a quantitative assessment of the accumulation and erosion of the sediments and resultant suspended radiocesium distribution around the river mouth and nearshore areas along the Fukushima Coast.

    18 Sep. 2019, AIP Conference Proceedings, 2157

    [Refereed]

    International conference proceedings

  • Yuki Kamidaira, Hideyuki Kawamura, Takuya Kobayashi, Yusuke Uchiyama

    © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Oceanic regional downscaling capability was implemented into Short-Term Emergency Assessment system of Marine Environmental Radioactivity (STEAMER) developed by Japan Atomic Energy Agency to enable us to predict more realistically the oceanic dispersion of radionuclides at higher spatiotemporal resolutions for broader applications. The system consisted of a double-nested oceanic downscaling circulation model with tidal forcing and an oceanic radionuclide dispersion model. This system was used to comparatively examine downscaling and tidal effects on the dispersion of radionuclides hypothetically released from the Fukushima Daiichi Nuclear Power Plant in the colder season. The simulated dissolved 137Cs distribution was different from that obtained using coarser-resolution models because downscaling enhanced both horizontal and vertical mixing. The suppression of horizontal mixing and the promotion of vertical mixing by tidal forcing synergistically reduced offshore 137Cs transport. In addition, the submesoscale effects strengthened the three-dimensional 137Cs fluctuations by <10 times, while the tidal effects promoted slightly increased the intensity of three-dimensional 137Cs fluctuations by approximately 3%. This indicated that the submesoscale effects substantially surpassed tidal forcing in oceanic mixing in the coastal margin off Fukushima in the colder season.

    03 Aug. 2019, Journal of Nuclear Science and Technology, 56 (8), 752 - 763

    [Refereed]

    Scientific journal

  • Xu Zhang, Yusuke Uchiyama, Akihiko Nakayama

    © 2019 Elsevier Ltd An Eulerian passive tracer model coupled with a quadruple-nested 3D circulation model was used to assess the coastal dispersal of treated wastewater effluent from a sewage treatment plant and the associated impacts on an adjacent seaweed farm using three different operational scenarios. When the discharged volume and source effluent fluxes were decreased by ~16.7%, the accumulated effluent in the farm was reduced by ~25.4%. A tracer flux budget analysis revealed the apparent predominance of the transient component that accounts for the nonlinear interactions primarily from tidal currents and eddies. The transient flux promoted the effluent influx to impede effluent accumulation in the farm, whereas the mean flux contributed to the outgoing flux. A source flux reduction caused a remarkable decrease in the transient flux and thus an even greater effluent accumulation reduction. In turn, a modified source density scenario without total effluent volume change did not work as expected.

    Jul. 2019, Marine Pollution Bulletin, 144, 265 - 274

    [Refereed]

    Scientific journal

  • Yusuke Uchiyama

    © 2019 Elsevier Ltd All rights reserved. Surface gravity waves are most familiar form of wave motions occurring at the interface between the atmosphere and water, which we see on ponds, lakes, and oceans. They are mainly wind driven, restored by gravity, and oscillating at a period of O(1-10) s. Shorter waves are also affected by surface tension, called capillary waves. In this article, linear and weakly nonlinear dynamics of surface gravity and capillary waves are described in the context of inviscid, incompressive, and irrotational fluids. Wave-current interactions, resonant wave-wave interactions, parasitic capillary waves, and wave breaking are also outlined.

    01 Jan. 2019, Encyclopedia of Ocean Sciences, 672 - 681

    [Refereed]

    In book

  • Natsuki TOKUNAGA, Yusuke UCHIYAMA, Daisuke TSUMUNE, Masatoshi YAMADA, Yutaka TATEDA, Takashi ISHIMARU, Yukari ITO, Yutaka WATANABE, Ken IKEHARA, Miho FUKUDA

    Corresponding, Japan Society of Civil Engineers, 2019, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 75 (2), I_667 - I_672

    [Refereed]

    Scientific journal

  • Naru TAKAURA, Yusuke UCHIYAMA, Nizamani ZAFARULLAH, Akihiko NAKAYAMA

    Corresponding, Japan Society of Civil Engineers, 2019, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 75 (2), I_979 - I_984

    [Refereed]

    Scientific journal

  • Waku KIMURA, Eiji MASUNAGA, Taichi KOSAKO, Yusuke UCHIYAMA

    Japan Society of Civil Engineers, 2019, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 75 (2), I_211 - I_216

    [Refereed]

    Scientific journal

  • Nobue OKADA, Yusuke UCHIYAMA

    Corresponding, Japan Society of Civil Engineers, 2019, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 75 (2), I_199 - I_204

    [Refereed]

    Scientific journal

  • RAINFALL OBSERVATION IN THE COASTAL AREA WITH OPTICAL DISDROMETERS IN THE SUMMER OF 2013

    岡地 寛季, 山田 朋人, 渡部 靖憲, 猿渡 亜由未, 大塚 淳一, 森 信人, 馬場 康之, 久保 輝広, 二宮 順一, 内山 雄介, 水谷 英郎

    土木学会, 2019, 地球環境研究論文集 : 地球環境シンポジウム, 27, 41 - 46, Japanese

    [Refereed]

  • Yuhan Cao, Changming Dong, Yusuke Uchiyama, Jin Wang, Xunqiang Yin

    ©2018. American Geophysical Union. All Rights Reserved. A numerical wave model is applied to study the wind-generated wave in the Southern California Bight (SCB). Observational data available in this area are used to validate the numerical model results. The model is integrated for 10 years (2004–2013). The comparison of the model results with observations shows that the model well reproduces the wave variations in the SCB. The multiple-scale variations in the wavefield are examined: interannual, seasonal, intraseasonal, and diurnal. The significant wave height and swell wave height distributions display distinct patterns during different seasons. On the interannual scale, the wave variation in the SCB is influenced by El Niño–Southern Oscillation activities. Intraseasonal scale events occur frequently. Land/sea breezes cause the diurnal variation. The effects of topography (especially islands) and currents on waves are analyzed. The islands in the SCB provide significant sheltering effects to the coast from deep-ocean waves. The effect of background currents on waves is discussed.

    Dec. 2018, Journal of Geophysical Research: Oceans, 123 (12), 9340 - 9356, English

    [Refereed]

    Scientific journal

  • Yusuke Uchiyama, Sachika Odani, Motohiko Kashima, Yuki Kamidaira, Satoshi Mitarai

    ©2018. American Geophysical Union. All Rights Reserved. For the preservation and protection of coral habitats along the Nansei Archipelago in the East China Sea, a submesoscale eddy-resolving synoptic ocean model was developed based on the Regional Oceanic Modeling System coupled with a 3-D Lagrangian particle tracking model. Millions of neutrally buoyant particles representing coral spawn and larvae were released from 19 major islands and one lagoon every spring from 2012 to 2015. The model results were compared to satellite data, in situ observation, and surface drifters to confirm reasonable agreement. The connectivity matrix across the archipelago was quantified using Lagrangian probability density functions of the modeled particle displacement. Most particles remained near the release areas, while some traveled long distances by the northeastward drifting Kuroshio, leading to notable interisland coral transport across the archipelago that promotes interisland connectivity. A possible mechanism was examined by analyzing the transition from coastal to pelagic transport of the particles released from the Yaeyama Islands, the southernmost area of the archipelago. The Kuroshio trapped the particles released from the northern coast of the islands with considerable temporal variability in the entrainment rate. By contrast, particles released from the southern coast are markedly affected by the eastward current around the release sites, which significantly reduces their entrainment in the Kuroshio and, thus, long-distance transport. Some entrained particles were expelled abruptly from the Kuroshio, trapped by the southwestward drifting Kuroshio Counter Current developed between the Kuroshio and the archipelago, and subsequently transported eastward to the islands.

    Dec. 2018, Journal of Geophysical Research: Oceans, 123 (12), 9245 - 9265, English

    [Refereed]

    Scientific journal

  • Okada, N, Uchiyama, Y, Tada, H, Endo, S, Baba, Y, Mizutani, H, Kubo, T, Mori, N, Watanabe, Y, Ohtsuka, J, Yamada, T, Saruwatari, A, Ninomiya, J

    Nov. 2018, 土木学会論文集B2(海岸工学), 74 (2), I_667─I_672, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Miyagawa, T, Odani, S, Kamidaira, Y

    Nov. 2018, 土木学会論文集B2(海岸工学), 74 (2), I_1291─I_1296, Japanese

    [Refereed]

    Scientific journal

  • Saruwatari, A, Sakagawa, R, Ohtsuka, J, Baba, Y, Kubo, T, Mizutani, H, Ninomiya, J, Yamada, T, Uchiyama, Y, Mori, N, Watanabe, Y

    Nov. 2018, 土木学会論文集B2(海岸工学), 74 (2), I_67─I_72, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Sengo, N, Kurosawa, K

    Nov. 2018, 土木学会論文集B2(海岸工学), 74 (2), I_625─I_630, Japanese

    [Refereed]

    Scientific journal

  • James C. McWilliams, Cigdem Akan, Yusuke Uchiyama

    © 2018 Cambridge University PressÂ. Coherent vortices with horizontal swirl arise spontaneously in the wave-driven nearshore surf zone. Here, a demonstration is made of the much greater robustness of coherent barotropic dipole vortices on a sloping beach in a 2D shallow-water model compared with fully 3D models either without or with stable density stratification. The explanation is that active vortex tilting and stretching or instability in 3D disrupt an initially barotropic dipole vortex. Without stratification in 3D, the vorticity retains a dipole envelope structure but is internally fragmented. With stratification in 3D, the disrupted vortex reforms as a coherent but weaker surface-intensified baroclinic dipole vortex. An implication is that barotropic or depth-integrated dynamical models of the wave-driven surf zone misrepresent an important aspect of surf-eddy behaviour.

    10 Sep. 2018, Journal of Fluid Mechanics, 850 (R2), R21 - R212, English

    [Refereed]

    Scientific journal

  • Development of a coupled HYCOM-ROMS downscaling ocean modeling system and its application to the South China Sea

    Uchiyama, Y, Sengo, N, Kurosawa, K, Nakayama, A

    Sep. 2018, Proc. 13th International Conference on Hydrodynamics (ICHD2018), 358–363, English

    [Refereed]

    International conference proceedings

  • A Lagrangian analysis on coastal dispersal of larvae and spawn around Okinawa Island, Japan

    Uchiyama, Y, Miyagawa, T, Odani, S, Mitarai, S

    Sep. 2018, Proc. 13th International Conference on Hydrodynamics (ICHD2018), 182–188, English

    [Refereed]

    International conference proceedings

  • Yusuke Uchiyama, Ryosuke Kanki, Akiko Takano, Hidekatsu Yamazaki, Yasumasa Miyazawa

    © 2017, © 2017 Taylor & Francis. For dynamically consistent, high-resolution, yet cost-effective regional oceanic downscaling modelling, an empirical three-dimensional (3D) density estimate based on publicly available datasets is utilized for the Regional Oceanic Modeling System (ROMS) with simple data assimilation (i.e., TS nudging, where TS stands for temperature and salinity). We rely on a method built upon the two-layer model to reconstruct a mesoscale 3D temperature and salinity field, referred to as Tokyo University of Marine Science and Technology (TUMSAT)-TS, using near real-time altimeter-derived dynamic height along with Argo float profiling data. The TUMSAT-TS is first validated using in situ hydrographic data, then is implemented in the Japan Coastal Ocean Predictability Experiment (JCOPE2)-ROMS downscaling system for the Kuroshio region off Japan. We explore the usability of TUMSAT-TS by carrying out three comparative simulations with temperature and salinity nudging towards the (i) TUMSAT-TS and (ii) JCOPE2-TS fields, and (iii) without the nudging. Whereas the unassimilated case fails to properly account for the Kuroshio, both datasets individually are found to help reproduce the mesoscale variability of the Kuroshio, as well as its transient paths, volume transport, associated kinetic energy (KE) and eddy KE, and seasonally varying stratification.

    08 Aug. 2018, Atmosphere - Ocean, 56 (4), 212 - 229, English

    [Refereed]

    Scientific journal

  • Yusuke Uchiyama, Xu Zhang, Yota Suzue, Taichi Kosako, Yasumasa Miyazawa, Akihiko Nakayama

    © 2018 Elsevier Ltd A high-resolution 3-D model was developed to assess the impact of a diversion outfall at the Tarumi Sewage Treatment Plant (TSTP) on an adjacent seaweed farm in Osaka Bay, Japan. The model was extensively validated to ensure a reasonable agreement with in situ observations. The western part of the farm is largely influenced by tidal currents, whereas the eastern area is mainly affected by subtidal residual currents that are primarily due to surface wind stress. The released effluent is transported by counterclockwise residual circulation formed off the TSTP. The model reveals that the diversion adequately suppresses the influence on the farm. While the instantaneous effluent concentration is diminished by about 50%, the effluent accumulated on the farm decreased from 2.83 × 104 m3 to 2.01 × 104 m3 due to the diversion, demonstrating an approximately 28% reduction of the effluent from the TSTP by the diversion outfall.

    May 2018, Marine Pollution Bulletin, 130, 40 - 54, English

    [Refereed]

    Scientific journal

  • Yuki Kamidaira, Yusuke Uchiyama, Hideyuki Kawamura, Takuya Kobayashi, Akiko Furuno

    © 2018. American Geophysical Union. All Rights Reserved. This study developed a submesoscale eddy-resolving oceanic dispersal modeling system comprising a double-nested oceanic downscaling model and an offline oceanic radionuclide dispersion model. This was used to investigate the influences of submesoscale coherent structures (SCSs) and associated ageostrophic secondary circulations (ASCs) on the three-dimensional (3-D) dispersal of dissolved cesium-137 (137Cs) released from the Fukushima Daiichi Nuclear Power Plant (FNPP1). Extensive model-data comparison demonstrated that the innermost high-resolution model, with a lateral grid resolution of 1 km, could successfully reproduce transient mesoscale oceanic structures, the Kuroshio path and stratification, and spatiotemporal variations of 137Cs concentrations. Using an accompanying mesoscale eddy-resolving model (grid resolution: 10 km) as a guide, we showed that submesoscale dynamics are important for improved representation of both the eddy field and the resultant 3-D dispersal of 137Cs, with the temporal variability of surface 137Cs near the FNPP1 being equivalent to that in the coarse-resolution model. According to energy conversion and spectral analyses, SCSs and ASCs occur most intensively on the submesoscale, primarily because of shear instability. However, baroclinic instability serves as a secondary mechanism. SCSs have prominent seasonality, reflected by intensification in the colder months, which is when the FNPP1 accident occurred. Analysis of the vertical flux of 137Cs was performed by decomposition of the variables into eddy, mesoscale, and submesoscale components using frequency and wave number filters. It revealed that 42.7% of the FNPP1-derived 137Cs was transported downward below the mixed layer by eddies with the major contribution being from ASCs induced by submesoscale eddies.

    Apr. 2018, Journal of Geophysical Research: Oceans, 123 (4), 2808 - 2828, English

    [Refereed]

    Scientific journal

  • Eiji Masunaga, Yusuke Uchiyama, Yota Suzue, Hidekatsu Yamazaki

    ©2018. American Geophysical Union. All Rights Reserved. This study investigates the dynamics of tidally induced internal waves over a shallow ridge, the Izu-Ogasawara Ridge off the Japanese mainland, using a downscaled high-resolution regional ocean numerical model. Both the Kuroshio and tides contribute to the field of currents in the study area. The model results show strong internal tidal energy fluxes over the ridge, exceeding 3.5 kW m−1, which are higher than the fluxes along the Japanese mainland. The flux in the upstream side of the Kuroshio is enhanced by an interaction of internal waves and currents. The tidal forcing induces 92% of the total internal wave energy flux, exhibiting the considerable dominance of tides in internal waves. The tidal forcing enhances the kinetic energy, particularly in the northern area of the ridge where the Kuroshio Current is not a direct influence. The tidal forcing contributes to roughly 30% of the total kinetic energy in the study area.

    Apr. 2018, Geophysical Research Letters, 45 (8), 3550 - 3558, English

    [Refereed]

    Scientific journal

  • Hiroaki Tada, Yusuke Uchiyama, Eiji Masunaga

    © 2017 Elsevier Ltd High-resolution downscaling ocean modeling was conducted to investigate the impacts of two super typhoons on the Kuroshio in the fall of 2014 off the Kyushu and Shikoku Islands, Japan. The model result was compared with field observations and satellite altimetry. The synoptic and mesoscale oceanic structures around the Kuroshio exhibit a good reproducibility. The typhoons generated near-inertial oscillations (NIOs) and near-inertial internal waves (NIIWs) around the Kuroshio path, particularly on the right side of the typhoon tracks. The NIOs developed in the mixed layer to alter the direction of the Kuroshio by ~30°. The associated velocity off the Shikoku and Kyushu Islands was significantly decelerated by ~0.2 ms−1. The velocity almost vanished off Kyushu Island and thus induced an unstable fluctuating path shortly after both typhoons passed over that region. The NIIWs were also excited at the thermocline, resulting in the oscillation of the Kuroshio path occurred in the entire water column. In contrast, off Shikoku Island, the typhoons shifted the Kuroshio path northward to enhance the interactions with the topographies. This shift caused considerable eddy shedding from the capes that resulted in mesoscale counterclockwise circulations as cyclonic quasi-standing eddies with a shedding period of ~3 days in the north of the Kuroshio path. The magnitude, direction, and meridional location of the path of the Kuroshio prominently fluctuated with the propagation of these eddies, manifested off Shikoku Island. Furthermore, these eddies induced sporadic northward intrusions of the Kuroshio warm water through the Kii Channel into the Seto Inland Sea (SIS), where a weak but persisting southward outflow prevails under normal conditions. Therefore, the process could collectively be called the “typhoon-Kuroshio-eddy interaction” which conceptually differs from the “typhoon-eddy-Kuroshio interaction” in the previous studies, where the Kuroshio was modulated by eddy collision. The wind stress curl and intrusions associated with the typhoons jointly provoked the inversion of the counterclockwise SIS residual circulation. The resultant spatially averaged volume flux was ~8 times as high as that under normal conditions.

    Feb. 2018, Deep-Sea Research Part I: Oceanographic Research Papers, 132, 80 - 93, English

    [Refereed]

    Scientific journal

  • HIGASHI Hironori, SATO Yoshinobu, YOSHINARI Hiroshi, MAKI Hideaki, KOSHIKAWA Hiroshi, KANAYA Gen, UCHIYAMA Yusuke

     Freshwater discharge from watersheds is one of the important boundary conditions for coastal hydrodynamic simulations, but its available observations are very limited at small rivers. The present study developed a hydrological discharge and coastal hydrodynamic model with high resolution for Seto Inland Sea and its all river basins. Using this model, we evaluated freshwater discharge to the sea for the period of 2007–2015 and investigated impacts of small rivers on reproducibility of coastal hydrodynamic simulation. The hydrological simulation indicated that total annual amount of freshwater discharge to the sea was 53.0 km3/yr; 68% was from 21 major rivers and 32% was from small rivers. The coastal hydrodynamic simulation overestimated sea surface salinity if the freshwater discharge only from the major rivers was given; reproduced well if all rivers were considered.

    Japan Society of Civil Engineers, 2018, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 74 (2), I_1135 - I_1140, Japanese

    [Refereed]

    Scientific journal

  • Daniel P. Dauhajre, James C. McWilliams, Yusuke Uchiyama

    © 2017 American Meteorological Society. Discovery and analysis of submesoscale variability O(0.3-30) km on the continental shelf is made possible by a high-resolution (Δx = 75 m) Regional Oceanic Modeling System (ROMS) simulation of the Southern California Bight (SCB). This variability is manifest in ubiquitous yet ephemeral coherent structures: fronts, filaments, and vortices. Similar to their open-ocean counterparts, fronts and filaments on the shelf are identified by their strong vertical velocity, surface convergence, cyclonic vorticity, and horizontal density gradient. Life cycles of these features typically last 3-5 days, with the formation dominated by a horizontal advective tendency that increases density and velocity gradients (i.e., frontogenesis). The shape of the coastline and depth of the water column both influence the abundance and spatial orientation of shallow-water fronts and filaments. Closer to shore, fronts and filaments often align themselves parallel to isobaths, and headlands often act as sites of intense vorticity generation through bottom stress. A quasi-steady, approximate momentum balance among rotation, pressure gradient, and vertical mixing-known as turbulent thermal wind (TTW)-often is valid in the strong secondary circulations local to fronts and filaments. However, front and filament circulations subject to strong diurnal variation in surface heating and vertical mixing are inconsistent with steady-state TTW balance. The secondary circulations can induce ephemeral material trapping and substantial vertical heat fluxes on the shelf.

    AMER METEOROLOGICAL SOC, 01 Dec. 2017, Journal of Physical Oceanography, 47 (12), 2949 - 2976, English

    [Refereed]

    Scientific journal

  • Odani, S, Uchiyama, Y, Kashima, M, Kamidaira, Y, Mitarai, S

     Ryukyu Islands in the East China Sea are in a subtropical climate, hosting desirable environment for abundant coral ecosystem. It is anticipated that the Kuroshio and associated eddy mixing promote the transport and dispersal of coral spawn and larvae across the islands, whereas the area has suffered from coral bleaching in the recent decades. Toward optimal preservation and protection of the coral habitats around Ryukyu Island, we conduct a double nested high-resolution synoptic ocean modeling using ROMS with grid spacing down to 600 m coupled with an offline Lagrangian particle tracking model. The modeled dispersal of coral spawn and larvae released from 18 major islands and lagoons are examined to quantify connectivity using Lagrangian probability density functions (PDFs) of the Lagrangian particles among Ryukyu Islands. The PDF analyses suggest that the particles mostly remain near the released areas, while about 10% of the particles are entrained in the Kuroshio to travel long distance, contributing to inter-island connectivity. Some of these particles are further transported northeastward, and then partially trapped by the Kuroshio Counter Current formed between the Kuroshio and the islands to approach Okinawa Main Island. We reveal that eastward current occurred in the south the Sekisei Lagoon shortly after the releases significantly suppresses the entrainment and the resultant long-distance transport.

    Japan Society of Civil Engineers, Nov. 2017, 土木学会論文集B2(海岸工学), 73 (2), I_1315 - I_1320, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Aduma, K, Odani, S, Iwasaki, T, Tsumune, D, Kamidaira, Y, Shimizu, Y, Onda, Y

     Niida River is well know to supply highly contaminated suspended 137Cs originated from the Fukushima Nuclear Power Plant to the ocean. We examine the oceanic dispersal and inventories of the sediments and suspended 137Cs in the ocean floor derived from Niida River, using the quadraple nested JCOPE2-ROMS 3D circulation model in a very high resolution configuration, coupled with a 3D multi-class sediment transport model, the iRIC-Nays 2DH river sediment model, the SWAN spectral wave model, and a static 137Cs absorption model. We focus on the storm and flood event associated with Typhoon 201326 (Wipha) passed off the Fukushima Coast, which provoked an enomous amount of riverine fluxes, to quantitatively assess the accumulation and erosion of the sediments and resultant suspended 137Cs inventories around the river mouth and nearshore areas.

    Japan Society of Civil Engineers, Nov. 2017, 土木学会論文集B2(海岸工学), 73 (2), I_685 - I_690, Japanese

    [Refereed]

    Scientific journal

  • Suzue, Y, Uchiyama, Y, Yamazaki, H

     The Kuroshio off Japan is accompanied by vigorous eddy and frontal activity both on meso- and submesoscales, which significantly affects the biogeochemical productivity in the upper ocean. We examine the seasonal variability of eddy-induced nitrate transport and resultant biogeochemical response around the Kuroshio using a climatological ROMS-NPZD model. A nitrogen budget analysis indicates that nitrogen exists mostly in the phyto- and zooplankton compartments in both the Kuroshio and Kuroshio Extension regions during the sping bloom. The increased zooplankton further enriches detritus that settles down by about 100 m, leading to an increase of ammonium below the mixed layer. In winter, eddy-induced nitrate transport is enhanced in the region about 1° away from the Kuroshio axis. The baroclinic instability due to the surface cooling in winter generates meso- and submesoscale eddies and substantially promotes eddy-induced vertical nitrate transport.

    Japan Society of Civil Engineers, Nov. 2017, 土木学会論文集B2(海岸工学), 73 (2), I_457 - I_462, Japanese

    [Refereed]

    Scientific journal

  • Masunaga, E, Suzue, Y, Uchiyama, Y, Yamazaki, H

     Regional Oceanic Numerical simulations using ROMS with tidal forcing were conducted to investigate tidally induced internal waves (internal tides) in the vicinity of the Izu-chain Islands. The tides enhance the enrgy flux of internal waves by about 10 times as large around the islands. Therefore, in the study region, the internal waves are considerably enargized by the tidal forcing. Although the total and baroclinic components of kinetic eneygy increase due to the tides, the barotropic kinetic energy component decreased by the tidal forcing. The internal waves accompanied by strong baroclinic flows largely contribute to the flow compared to the currents due to winds and the Kuroshio. The numerical simulateons also revealed the enhanced eddy motiions due to the tidal forcing, suggesting that the tides contiribute to lateral mixing or transports via meso- and submesoscale eddies.

    Japan Society of Civil Engineers, Nov. 2017, 土木学会論文集B2(海岸工学), 73 (2), I_451 - I_456, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Okada, N, Kurosawa, K

     Kinematics, dynamics, and statistical nature of mesoscale oceanic eddies and their effects on the Kuroshio are investigated using a velocity-based automated eddy detection and tracking algorithm proposed by Nencioli et al. (2010) to apply to a 20-year long satellite altimetry dataset provided by AVISO for the entire North Pacific (NP) basin. In the NP, barotropic instability associated primarily with topographic shear and frontal baroclinic instability concurrently promote generation of mesoscale eddies. The eddy sizes and magnitudes of relative and absolute vorticity are inversely correlated, which is well explained by inertial instability and potential vorticity conservation, in particular in the Kuroshio Extension region (KE) and Subtropical Zonal Band (SZB), where eddy kinetic energy is highest in the NP. Mesoscale eddies generally propagate westward as non-dispersive, first-mode baroclinic Rossby waves in the SZB and U.S. West Coast, according to a frequenc-ywavenumber spectral analysis. In contrast, the eddies in the KE are rather multi-directional with notable eastward propagation due to eastward eddy shedding from the eastward-drifting Kuroshio. Furthermore, we show two selected examples, in which mesoscale eddies collided with the Kuroshio to provoke and suppress meander of its path off the continental shelf off Japan.

    Japan Society of Civil Engineers, Nov. 2017, 土木学会論文集B2(海岸工学), 73 (2), I_1429 - I_1437, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Kanki, R, Takano, A, Yamazaki, H, Miyazawa, Y

    Nov. 2017, Atmosphere-Ocean, 55, 1 - 18, English

    [Refereed]

    Scientific journal

  • Kurosawa, K, Uchiyama, Y, Miyoshi, T

     Ocean data assimilation (DA) has widely been used for various engineering purposes including monitoring, forecast, and port operations. However, in semi-enclosed estuaries such as the Seto Inland Sea (SIS), Japan, DA has rarely been adapted because satellite data and Argo floats are desperatively unavailable, albeit being essential to successful oceanic predictions. In the present study, we develop a DA system toward rigorous predictions optimal for relatively small coastal and estuarine settings. The system consists of a three-dimensional variational (3DVAR) assimilation scheme being made compatible with ROMS using an in-situ dataset available for the SIS. The DA system significantly improves the reproducibility of water temperature and salinity fields from those without DA. We show an evidence that detailed terrestrial freshwater discharge data is inevitable for more accurate salinity predictions in the estuary.

    Japan Society of Civil Engineers, Nov. 2017, 土木学会論文集B2(海岸工学), 73 (2), I_1663 - I_1668, Japanese

    [Refereed]

    Scientific journal

  • Yuki Kamidaira, Yusuke Uchiyama, Satoshi Mitarai

    In this study, an oceanic downscaling model in a double-nested configuration was used to investigate the role played by the Kuroshio warm current in preserving and maintaining biological diversity in the coral coasts around the Ryukyu Islands (Japan). A comparison of the modeled data demonstrated that the innermost submesoscale eddy-resolving model successfully reproduced the synoptic and mesoscale oceanic structures even without data assimilation. The Kuroshio flows on the shelf break of the East China Sea approximately 150-200 km from the islands; therefore, eddy-induced transient processes are essential to the lateral transport of material within the strip between the Kuroshio and the islands. The model indicated an evident predominance of submesoscale anticyclonic eddies over cyclonic eddies near the surface of this strip. An energy conversion analysis relevant to the eddy-generation mechanisms revealed that a combination of both the shear instability due to the Kuroshio and the topography and baroclinic instability around the Kuroshio front jointly provoke these near-surface anticyclonic eddies, as well as the subsurface cyclonic eddies that are shed around the shelf break. Both surface and subsurface eddies fit within the submesoscale, and they are energized more as the grid resolution of the model is increased. An eddy heat flux (EHF) analysis was performed with decomposition into the divergent (dEHF) and rotational (rEHF) components. The rEHF vectors appeared along the temperature variance contours by following the Kuroshio, whereas the dEHF properly measured the transverse transport normal to the Kuroshio's path. The diagnostic EHF analysis demonstrated that an asymmetric dEHF occurs within the surface mixed layer, which promotes eastward transport toward the islands. Conversely, below the mixed layer, a negative dEHF tongue is formed that promotes the subsurface westward warm water transport.

    PERGAMON-ELSEVIER SCIENCE LTD, Jul. 2017, CONTINENTAL SHELF RESEARCH, 143, 206 - 218, English

    [Refereed]

    Scientific journal

  • Yusuke Uchiyama, James C. McWilliams, Cigdem Akan

    The ROMS-WEC model [Uchiyama et al., 2010] based on an Eulerian wave-averaged vortex-force asymptotic theory of McWilliams et al. (2004) is applied to analyze 3-D transient wave-driven rip currents and associated intrinsic very low-frequency (VLF) variability in the surf zone on a surveyed bathymetry under spatiotemporally uniform offshore incident waves. The 3-D rip currents are substantially depth-dependent due to the vertical recirculation, composed of pairs of counter-rotating longitudinal overturning roll cells that promote surface convergence. The vortex force plays an important role in vorticity budget, preconditioning overall vorticity reduction. These rip currents are intrinsically unstable and contribute about 70% to kinetic energy (KE) as eddy kinetic energy (EKE), consistent with observations. The dominant fluctuation period fits the VLF band, at about 18 min. The current effect on waves (CEW) alters not only the mean rip structure, but also the associated turbulence as the modified cross-shore EKE profile with considerable accentuation in the inner surf zone. Increased alongshore bathymetric variability proportionally intensifies KE and intrinsic EKE, whereas it reduces the VLF period. With a guide of a pseudo 2D model, we reveal that vortex tilting effect due to the horizontal vorticity inherent in the 3-D rip currents promotes collapse of the 3-D eddies through an enhanced forward kinetic energy cascade, leading to short-lived, laterally-stretched 3-D eddies resulting in elongated filaments that decay more quickly than coherent, long-lived, circular 2-D eddies.

    AMER GEOPHYSICAL UNION, Jul. 2017, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 122 (7), 5826 - 5849, English

    [Refereed]

    Scientific journal

  • Yuki Kamidaira, Yusuke Uchiyama, Satoshi Mitarai

    In this study, an oceanic downscaling model in a double-nested configuration was used to investigate the role played by the Kuroshio warm current in preserving and maintaining biological diversity in the coral coasts around the Ryukyu Islands (Japan). A comparison of the modeled data demonstrated that the innermost submesoscale eddy-resolving model successfully reproduced the synoptic and mesoscale oceanic structures even without data assimilation. The Kuroshio flows on the shelf break of the East China Sea approximately 150-200 km from the islands; therefore, eddy-induced transient processes are essential to the lateral transport of material within the strip between the Kuroshio and the islands. The model indicated an evident predominance of submesoscale anticyclonic eddies over cyclonic eddies near the surface of this strip. An energy conversion analysis relevant to the eddy-generation mechanisms revealed that a combination of both the shear instability due to the Kuroshio and the topography and baroclinic instability around the Kuroshio front jointly provoke these near-surface anticyclonic eddies, as well as the subsurface cyclonic eddies that are shed around the shelf break. Both surface and subsurface eddies fit within the submesoscale, and they are energized more as the grid resolution of the model is increased. An eddy heat flux (EHF) analysis was performed with decomposition into the divergent (dEHF) and rotational (rEHF) components. The rEHF vectors appeared along the temperature variance contours by following the Kuroshio, whereas the dEHF properly measured the transverse transport normal to the Kuroshio's path. The diagnostic EHF analysis demonstrated that an asymmetric dEHF occurs within the surface mixed layer, which promotes eastward transport toward the islands. Conversely, below the mixed layer, a negative dEHF tongue is formed that promotes the subsurface westward warm water transport.

    PERGAMON-ELSEVIER SCIENCE LTD, Jul. 2017, CONTINENTAL SHELF RESEARCH, 143, 206 - 218, English

    [Refereed]

    Scientific journal

  • Yusuke Uchiyama, Yota Suzue, Hidekatsu Yamazaki

    The Kuroshio is one of the most energetic western boundary currents accompanied by vigorous eddy activity both on mesoscale and submesoscale, which affects biogeochemical processes in the upper ocean. We examine the primary production around the Kuroshio off Japan using a climatological ocean modeling based on the Regional Oceanic Modeling System (ROMS) coupled with a nitrogen-based nutrient, phytoplankton and zooplankton, and detritus (NPZD) biogeochemical model in a submesoscale eddy-permitting configuration. The model indicates significant differences of the biogeochemical responses to eddy activities in the Kuroshio Region (KR) and Kuroshio Extension Region (KE). In the KR, persisting cyclonic eddies developed between the Kuroshio and coastline are responsible for upwelling-induced eutrophication. However, the eddy-induced vertical nutrient flux counteracts and promotes pronounced southward and downward diapycnal nutrient transport from the mixed-layer down beneath the main body of the Kuroshio, which suppresses the near-surface productivity. In contrast, the KE has a 23.5% higher productivity than the KR, even at comparable eddy intensity. Upward nutrient transport prevails near the surface due to predominant cyclonic eddies, particularly to the north of the KE, where the downward transport barely occurs, except at depths deeper than 400 m and to a much smaller degree than in the KR. The eddy energy conversion analysis reveals that the combination of shear instability around the mainstream of the Kuroshio with prominent baroclinic instability near the Kuroshio front is essential for the generation of eddies in the KR, leading to the increase of the eddy-induced vertical nitrate transport around the Kuroshio.

    AMER GEOPHYSICAL UNION, Jun. 2017, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 122 (6), 5046 - 5062, English

    [Refereed]

    Scientific journal

  • 放射性物質の分散シミュレーションに影響を及ぼす沿海域海況変動過程とその再現性

    Masumoto, Y, Tsumune, D, Guo, X, Uchiyama, Y, Miyazawa, Y

    Feb. 2017, 沿岸海洋研究, 54 (2), 151 - 157, Japanese

    [Refereed][Invited]

    Scientific journal

  • マルチクラス懸濁質輸送モデルを用いた福島沿岸域における河川由来懸濁質および懸濁態放射性核種の海洋分散について

    Uchiyama, Y

    Feb. 2017, 沿岸海洋研究, 54 (2), 159 - 172, Japanese

    [Refereed][Invited]

    Scientific journal

  • Uchiyama, Y, Suzue, Y, Kosako, T

    Jan. 2017, 土木学会論文集B1(水工学), 72 (4), I_949 - I_954, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Yoshiki, T, Tada, H, Baba,Y, Mizutani,H, Kubo, T, Mori, N, Saruwatari, A, Otsuka, J, Ninomiya,J, Watanabe, Y, Yamada, T

    For rigorious description of upper ocean dynamics and resultant volume transport at the mouth of Tanabe Bay, Wakayama, Japan, a comprehensive field campaign was conducted from summer to fall of 2015. The vertical structure of transient dynamics in the surface boundary layer and consequent water exchange at the mouth are characterized by high-frequency variability peaked at around the semi-diurnal period as well as in the lower-frequency subtidal band centered at 3 day period, consistent with the previous modeling study. A spectral coherence analysis indicates that near-surface currents are mainly driven by wind stress peaked at the diurnal frequency, whereas subsurface currents fluctuate rather by semi-diurnal internal tides. The upper ocean cools down gradually, corresponding to seasonal transition from summer to fall condition. However, an abrupt cooling event is observed albeit in a calm local forcing condition where an offshore subtidal cold water intrusion induced remotely by the fluctuating Kuroshio path plays an essential role.

    土木学会 = Japan Society of Civil Engineers, 15 Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_493 - I_498, Japanese

    [Refereed]

    Scientific journal

  • Kamidaira, Y, Kawamura, H, Kobayashi, T, Uchiyama, Y

     A downscaling oceanic dispersal modeling system has been developed. The system consists of double nested ROMS embedded in the MOVE assimilative reanalysis product and oceanic radionuclides dispersion model SEA-GEARN-FDM. The developed submesoscale eddy-resolving model is applied to reanalyses of the Fukushima accident occurred in March 2011. Model validations with satellite and in-situ data agreed well. The finest resolution model performed well between three models with different grid resolutions, suggesting that submesoscale eddies and associated vertical flows in the upper layer are substantial to three-dimensional behavior of the radionuclide. A diagnostic vertical 137Cs flux analysis demonstrates that ageostrophic secondary circulations induced by submesoscale eddies promote seasonaly-varying subduction of the 137Cs enhanced in spring, namely, immediately after the accident.

    Japan Society of Civil Engineers, Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_451 - I_456, Japanese

    [Refereed]

    Scientific journal

  • Kosako, T, Uchiyama, Y, Mitarai, S

    Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_1273 - I_1278, Japanese

    [Refereed]

    Scientific journal

  • Yamanishi, T, Uchiyama, Y, Iwasaki, T, Shimizu, Y, Tsumune, D, Misumi, K, Onda, Y

     We examine oceanic dispersal of the iRIC-Nays2DH-evaluated sediment and suspended 137Cs influxes from Niida River, Fukushima, with a particular attention to the first flood event in late May of 2011 after the Fukushima nuclear accident. Alongshore suspended 137Cs transport occurs assymetrically, comprising storm-driven southward transport confined in the shallow area due to shoreward Ekman transport associated with strong northerly wind, followed by northwestward widespread transport under mild southerly wind condition. About 70 % of the Niida River-derived suspended 137Cs remains near the mouth for 20 days after the flood event. Nevertheless, our model results as well as an observation suggest that the area is dominated by erosion as for high bed shear stress all the time, thus suspended radionuclides are redistributed to dissipate away in long term.

    Japan Society of Civil Engineers, Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_757 - I_762, Japanese

    [Refereed]

    Scientific journal

  • Tada, H, Uchiyama, Y

     A submesoscale eddy-permitting oceanic reanalysis is carried out with exploiting the JCOPE2-ROMS downscaling system forced by the JMA GPV-MSM atmospheric reanalysis with a particular attention to the two consecutive super typhoons Phanfone and Vongfong in the fall 2014. On the Pacific side of Japan off Shikoku Island, the Kuroshio main body oscillates horizontally and vertically upon collisions with near-inertial internal gravity waves maintained by inertial resonance in the mixed layer, followed by substantial alteration of the Kuroshio path in the downstream region. A velocity rotary spectrum extracts a distinct peak in the near-inertial frequency band on the offshore side of the Kuroshio with clockwise rotation due to near-inertial oscillations caused by the typhoons. On the coastal side, it peaks at around periods of about 3 days with counter-clockwise rotation, which correspond to the shedding frequency of mesoscale eddies released from Cape Ashizuri. These eddies are enhanced by the typhoons to promote oscillations of the Kuroshio axis at around the 3-day period.

    Japan Society of Civil Engineers, Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_457 - I_462, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Odani, S, Yamanishi, T, Kamidaira, Y, Mitarai, S

     Okinawa Island is located in the subtropical region of Japan, hosting ecologically abundant coral reefs even though they lie at the northernmost extreme of the habitable region. The island is situated on the ridge of Ryukyu Arc between East China Sea (ECS) and Ryukyu Trench (RT). The coral ecosystem in the west coast of the island is maintained by persistent intrusions of Kuroshio warm water. These factors lead to oceanic asymmetry between the both sides of the island. In this study, a triple nested downscaling ocean model based on ROMS is configured to examine the asymmetric oceanic structure around the island. The tidal harmonic and eddy kinetic energy analyses around the island clearly suggest that the southernmost area of the island, where Tokashiki strait (TS) lies between Okinawa Island and Tokashiki Island, plays a substantial role in controlling the asymmetric oceanic responses. The evaluated meridional volume flux normal to TS indicates seasonal variability with prominent ECS to RT transport in spring. The transport along TS is highly correlated with the volume transport of the southwestward current formed between the Kuroshio and the island, which is often referred to as the Kuroshio Counter Current (KCC). Surface vorticity indicates that the KCC consists of clockwise-rotating, anti-cyclonic mesoscale eddies. Relaxation of surface cooling and shallowing the mixed-layer depth occurred from winter to spring result in attenuating submesoscale eddies and promoting emergence of mesoscale eddies.

    Japan Society of Civil Engineers, Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_481 - I_486, Japanese

    [Refereed]

    Scientific journal

  • Kubo, S, Ninomiya, J, Mori, N, Baba, Y, Mizutani, H, Kubo, T, Uchiyama, Y, Watanabe, Y, Yamada, T, Otsuka, J, Saruwatari, A

     This study focuses on the process of thermocline's destruction and reformation during typhoons using field observation data. The thermocline has a large effect on the circulation and would be a factor to make water worse. Therefore, it is necessary to understand its process deeply. In this study, the stability of density stratification was evaluated based on the Brant-Vaisala frequency and the Richardson number. The results suggested that high wave destroyed the stratification and high wind mixed ocean water vertically more energetically during stratified season. On the other hand, is was found that stratification was unstable regardless of typhoon intensity during unstratified season. Moreover, the characteristics of water-mass were evaluated on the TS diagram during unstratified season.

    Japan Society of Civil Engineers, Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_487 - I_492, Japanese

    [Refereed]

    Scientific journal

  • Kosako, T, Uchiyama, Y

    Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_1279 - I_1284, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Kurosawa, K, Kosako, T, Tada, H

    Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_1549 - I_1554, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Suzue, Y, Yamazaki, H

     The Kuroshio is one of the most energetic western boundary currents accompanied by vigorous eddy activity both at meso- and submesoscales which significantly affect biogeochemical productivity in the upper ocean. We examine such processes with a climatological ocean modeling based on ROMS coupled with an NPZD model for the Kuroshio region off Japan. Cyclonic mesoscale eddies develop in the coastal area of Enshu Nada, leading to upward nutrient supply to euphotic zone with promoting active primary production. In contrast, Chl.a is much less prominent around the Kuroshio path where the higher EKE is distributed. The downward eddy-induced vertical nutrient flux occurs at depth beneath the Kuroshio path and the reduction of nutrient consequently takes place. Therefore, a substantial amount of nutrient is removed from the near-surface layer by eddy-driven downward nutrient transport, resulting in suppressing the primary production there.

    Japan Society of Civil Engineers, Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_1369 - I_1374, Japanese

    [Refereed]

    Scientific journal

  • Upper ocean dynamics and associated water exchange at the entrance of a semi-enclosed bay based on an in-situ ADCP measurement

    Yusuke Uchiyama, Tomomichi Yoshiki, Hiroaki Tada, Yasuyuki Baba, Hideaki Mizutani, Teruhiro Kubo, Nobuhito Mori, Ayumi Saruwatari, Junichi Otsuka, Junichi Ninomiya Yasunori, Watanabe,Tomohito Yamada

    Aug. 2016, AOGS 13th Annual Meeting (AOGS 2016)

    [Refereed]

  • Leonel Romero, David A. Siegel, James C. McWilliams, Yusuke Uchiyama, Charles Jones

    Characterizing the dispersion and dilution of storm water from small coastal creeks is important for understanding the importance of land-derived subsidies to nearby ecosystems and the management of anthropogenic pollutants. In Southern California, creek runoff is episodic, intense, and short-lived while the plumes are buoyant, all of which make the field sampling of freshwater plumes challenging. Numerical modeling offers a viable way to characterize these systems. The dilution and dispersion of freshwater from two creeks that discharge into the Santa Barbara Channel, California is investigated using Regional Ocean Modeling System (ROMS) simulations with a horizontal resolution of 100 m. Tight coupling is found among precipitation, hydrologic discharge, wind forcing, and submesoscale flow structures which all contribute to plume evolution. During flooding, plumes are narrow and attached to the coast, due to downwelling/onshore wind forcing and intense vorticity filaments lying parallel to the shelf. As the storm passes, the winds typically shift to offshore/upwelling favorable conditions and the plume is advected offshore which enhances its dilution. Plumes reach the bottom nearshore while they form thin layers a few meters thick offshore. Dilution field of passive tracers released with the runoff is strongly anisotropic with stronger crossshelf gradients than along-shelf. Dispersion analysis of statistical moments of the passive tracer distribution results in scale-dependent diffusivities consistent with the particle-pair analysis of Romero et al. (2013). Model validation, the roles of submesoscale processes, and wind forcing on plume evolution and application to ecological issues and marine resource management are discussed.

    AMER GEOPHYSICAL UNION, Jun. 2016, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 121 (6), 3926 - 3943, English

    [Refereed]

    Scientific journal

  • Nirnimesh Kumar, Falk Feddersen, Sutara Suanda, Yusuke Uchiyama, James McWilliams

    Accurately representing diurnal and semidiurnal internal variability is necessary to investigate inner-shelf to midshelf exchange processes. Here, a coupled Regional Ocean Model System (ROMS)-Simulating Waves Nearshore (SWAN) model is compared to observed diurnal and semidiurnal internal tidal variability on the mid and inner shelf (26-8 m water depth) near San Pedro Bay, California. Modeled mean stratification is about one-half of that observed. Modeled and observed baroclinic velocity rotary spectra are similar in the diurnal and semidiurnal band. Modeled and observed temperature spectra have similar diurnal and semidiurnal band structure, although the modeled is weaker. The observed and modeled diurnal and semidiurnal baroclinic velocity- and temperature-dominant vertical structures are similar and consistent with mode-one internal motions. Both observed and modeled diurnal baroclinic kinetic energy are strongly correlated to diurnal wind forcing and enhanced by subtidal vorticity-induced reduction in the inertial frequency. The mid- and inner-shelf modeled diurnal depth-integrated heat budget is a balance between advective heat flux divergence and temperature time derivative. Temperature-velocity phase indicates progressive semidiurnal internal tide on the midshelf and largely standing internal tide on the inner shelf in both observed and modeled. The ratio of observed to modeled inferred phase speed is consistent with the observed to modeled stratification. The San Pedro Bay modeled semidiurnal internal tide has significant spatial variability, variable incident wave angles, and multiple local generation sites. Overall, the coupled ROMS-SWAN model represents well the complex diurnal and semidiurnal internal variability from the mid to the inner shelf.

    AMER METEOROLOGICAL SOC, Mar. 2016, JOURNAL OF PHYSICAL OCEANOGRAPHY, 46 (3), 841 - 862, English

    [Refereed]

    Scientific journal

  • SARUWATARI Ayumi, NINOMIYA Junichi, WATANABE Yasunori, YAMADA Tomohito, OTSUKA Junichi, BABA Yasuyuki, MIZUTANI Hideaki, KUBO Teruhiro, UCHIYAMA Yusuke, MORI Nobuhito

    Sea spray is one of the important factors to affect weather conditions over the ocean in terms of constituting an aerosol as well as determining air-sea transport of heat, moisture and momentum. The final goal of this study is to explain the relationship between sea-spray generation and conditions of the atmosphere and ocean for a more accurate prediction of the amount of sea spray. This study conducted three-year field observations of atmospheric aerosol at an offshore observatory in Tanabe Bay, Wakayama. Large-scale (> 100 km) distribution of atmospheric aerosol was found to dominate the concentration of the observed aerosol less than 1 μm in normal weather conditions. During storm events with strong winds from the Pacific Ocean, however, the observed concentration monotonically increased with the wind speed, which is considered to be a result of the increase in oceanic aerosol derived from sea spray.

    Japan Society of Civil Engineers, 2016, Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)), 72 (2), I_537 - I_547, Japanese

    [Refereed]

    Scientific journal

  • Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2016

    Baba, Y, Mizutani, H, Kubo, T, Uchiyama, Y, Mori, N, Watanabe, Y, Yamada, T, Saruwatari, A, Otsuka, J, Ninomiya, J

    京都大学防災研究所, 2016, Annuals of Disas. Prev. Res. Inst., Kyoto Univ., 60 (60), 664 - 671, Japanese

    Research institution

  • Patrick Marchesiello, Rachid Benshila, Rafael Almar, Yusuke Uchiyama, James C. McWilliams, Alexander Shchepetkin

    Do lateral shear instabilities of nearshore circulation account for a substantial part of Very Low-Frequency (VLF) variability? If yes, it would promote stirring and mixing of coastal waters and surf-shelf exchanges. Another question is whether tridimensional transient processes are important for instability generation. An innovative modeling system with tridimensional wave-current interactions was designed to investigate transient nearshore currents and interactions between nearshore and innershelf circulations. We present here some validation of rip current modeling for the Aquitanian coast of France, using in-situ and remote video sensing. We then proceed to show the benefits of 3D versus 2D (depth-mean flow) modeling of rip currents and their low-frequency variability. It appears that a large part of VLF motions is due to intrinsic variability of the tridimensional flow. 3D models may thus provide a valuable, only marginally more expensive alternative to conventional 2D approaches that miss the vertical flow structure and its nonlinear interaction with the depth-averaged flow. (C) 2015 Published by Elsevier Ltd.

    ELSEVIER SCI LTD, Dec. 2015, OCEAN MODELLING, 96, 36 - 48, English

    [Refereed]

    Scientific journal

  • Kamidaira, Y, Uchiyama, Y, Mitarai, S, Nakada, S

    A synoptic, regional downscaling experiment of the Kuroshio off the Ryukyu Islands, Japan, forced by the JCOPE2 and GPV-MSM with a horizontal resolution of 1 km exhibits the evident predominance of submesoscale anticyclonic eddies over cyclones in the narrow strip between the Kuroshio and the islands (Uchiyama et al., 2013). In order to investigate submesoscale dynamics and associated lateral mixing around the Ryukyu Islands, we conduct an eddy heat flux (EHF) analysis on eddying currents. We specifically focus on the divergent component of the EHF (dEHF) that is responsible for the eddy heat transport normal to the Kuroshio. We show that the rotational EHF (rEHF) vectors follow the temperature variance contours while the dEHF properly measures the contribution of the normal component. The diagnostic EHF analysis suggests that these lateral eddy heat transport occurring asymmetrically relative to the Kuroshio axis is associated with submesoscale eddies due to the topographic shear.

    Japan Society of Civil Engineers, Nov. 2015, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 71 (2), 1219 - 1224, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Miyazaki, D, Kanki, R, Miyazawa, Y

    Seasonal variability of the subpolar front (SPF) and associated East Korea Warm Current (EKWC) and Tsushima Warm Current (TWC) is examined with the double nested JCOPE2-ROMS downscaling oceanic circulation model. The submesoscale (SMS) eddy-resolving model successfully reproduces the EKE trapping in the surface layer due to emergence of energetic SMS eddies mainly attributed to symmetric instability induced by surface cooling during winter and spring. The SMS eddy-driven horizontal stirring leads to weakening of the SPF, EKWC and TWC significantly. In turn, the decreased SMS mixing along with the increased influx from the Tsuhima Straight stabilize the EKWC and TWC to sharpen the SPF.

    Japan Society of Civil Engineers, Nov. 2015, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 71 (2), 415 - 420, Japanese

    [Refereed]

    Scientific journal

  • Yamanishi, T, Uchiyama, Y, Tsumune, D, Misumi, K

    Misumi et al. (2014) estimated suspended 137Cs concentration in the seabed by a mathematical model considering static adsorption and desorption of 137Cs between the seawater and the bed sediments. How-ever, the inferred bed 137Cs is substantially underestimated in the offshore area at depth deeper than 200 m. They attributed the reason of this discrepancy to nearshore-originated seaward sediment transport that is omitted in their model. Our model results reveal that although the land-derived or nearshore clay-class sediments reach the deeper area, the time-integrated deposition is only about 2.0×10-3 kg/m2 that is con-sidered to be a minor fraction. It is suggested that debris of organic matters and biogenic opal rather than land-derived minerals likely cause the offshore 137Cs deposition. We further examine nearshore dispersal patterns and quantify the 137Cs inventory in the land-derived sediments though the rivers.

    Japan Society of Civil Engineers, Nov. 2015, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 71 (2), 565 - 570, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Tada, H

    Typhoons alter the upper ocean dynamics and thermal structure, giving rise to feedback on the atmosphere. Intense ocean surface wind and barometric effects induce rough waves and storm surges that occasionally cause severe coastal disasters. For rigorous oceanic modeling under typhoon conditions, we implement the inverse barometer effect and the COAMPS bulk formula into ROMS. A submesoscale eddypermitting oceanic modeling is configured at a horizontal resolution of 2 km based on the JCOPE2-ROMS downscaling system forced by the JMA GPV-MSM atmospheric reanalysis. A retrospective, synoptic reanalysis is carried out with a particular focus on the two consecutive super typhoons Phanfone (#1418, Category 4, the lowest pressure was 935 hPa) and Vongfong (#1419, Cat. 5, 900 hPa) in the fall 2014. These typhoons abruptly amplify the volume outflux from the Seto Inland Sea (SIS) at the Bungo Channel, leading to the pronounced counter-clockwise circulation that opposes the clockwise overall SIS circulation under the normal condition. The model also successfully reproduces increased eddy kinetic energy below the typhoons with intense cyclonic positive vorticity driven by torque of the wind stress curl, not only at surface but also at depth down to about 100 m deep. These cyclones are cold-core mesoscale eddies with SST decrease by about 3°C associated with prominent mixed layer deepening.

    Japan Society of Civil Engineers, Nov. 2015, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 71 (2), 211 - 216, Japanese

    [Refereed]

    Scientific journal

  • Kosako, T, Uchiyama, Y, Mitarai, S

    We investigate influences of fluctuating Kuroshio path on circulation and larval dispersal in the Seto Inland Sea (SIS) using a massive amount of Lagrangian particles released from 83 patches in the modeled SIS circulation field with a double-nested, high-resolution ROMS configuration for the years 2004-2013. The clockwise overall circulation in the SIS is largely affected by the distances of the Kuroshio axis from the Capes Toi, Ashizuri, and Shionomisaki. Interanual and seasonal variability of the pelagedic larval dispersal is then examined with Lagrangian PDFs of the dispersed particles. The larval dispersal generally occurs eastward, maily cuased by the clockwise SIS circulation and thus the transient Kuroshio. In summer, however, the eastward larval dispersal is pronousedly altered by locally-developed anticyclonic gyres associated with the "cold dome" in the Iyo Sea and Harima Sea. In the Iyo Sea, the eastward transport is maintained by a relatively weak gyre, while it is rather reduced through trapping of a strong gyre in the Harima Sea. In winter, many of the larvae released from the Iyo Sea are transported westward due to the northerly winter monsoon, while the persisitent eastward transport is predominant in the Harima Sea.

    Japan Society of Civil Engineers, Nov. 2015, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 71 (2), 1231 - 1236, Japanese

    [Refereed]

    Scientific journal

  • Three-dimensional transient rip currents: Effects of topography on low-frequency motions

    Uchiyama, Y, Kawakami, M

    JSST, Oct. 2015, Proc. of 34th JSST Annual Conference: International Conference on Simulation Technology, 318 - 320, English

    [Refereed]

    International conference proceedings

  • Seasonal variability of Eulerian tracer dispersal in an estuary and a continental shelf margin

    Suzue, Y, Uchiyama, Y

    JSST, Oct. 2015, Proc. of 34th JSST Annual Conference: International Conference on Simulation Technology, 314 - 317, English

    [Refereed]

    International conference proceedings

  • Larval dispersal in the Seto Inland Sea analyzed with a 3-D Lagrangian particle tracking

    Kosako, T, Uchiyama, Y

    JSST, Oct. 2015, Proc. of 34th JSST Annual Conference: International Conference on Simulation Technology, 310 - 313, English

    [Refereed]

    International conference proceedings

  • Uchiyama, Y, Nishii, T

    Japan Society of Civil Engineers, Jun. 2015, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 71 (2), 383 - 388, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Suzue, Y, Kosako, T

    Japan Society of Civil Engineers, Jun. 2015, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 72 (4), I_949 - I_954, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Kanki, R, Takano, A, Yamazaki, H, Miyazawa, Y

    Japan Society of Civil Engineers, Jun. 2015, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 71 (2), 365 - 370, Japanese

    [Refereed]

    Scientific journal

  • Nirnimesh Kumar, Falk Feddersen, Yusuke Uchiyama, James McWilliams, William O'Reilly

    A coupled wave and circulation model that includes tide, wind, buoyancy, and wave processes is necessary to investigate tracer exchange in the shelf region. Here, a coupled Regional Ocean Model System (ROMS)-Simulating Waves Nearshore (SWAN) model, resolving midshelf to the surfzone region of the San Pedro Bay, California, is compared to observations from the 2006 Huntington Beach experiment. Waves are well modeled, and surfzone cross- and alongshore velocities are reasonably well modeled. Modeled and observed rotary velocity spectra compare well in subtidal and tidal bands, and temperature spectra compare well in the subtidal band. Observed and modeled mid- and inner-shelf subtidal velocity ellipses and temperature variability determined from the first vertical complex EOF (cEOF) mode have similar vertical structure. Although the modeled subtidal velocity vertical shear and stratification are weaker than observed, the ratio of stratification to shear is similar, suggesting model vertical mixing is consistent with observations. On fortnightly and longer time scales, the surface heat flux and advective heat flux divergence largely balance on the inner shelf and surfzone. The surfzone and inner-shelf alongshore currents separated by 220 m are unrelated. Both modeled and observed subtidal alongshelf current and temperature are cross-shelf coherent seaward of the surfzone. Wind forcing explains 50% of the observed and modeled inner-shelf alongshore current variability. The observed and modeled inner-shelf alongshelf nonuniformities in depth-averaged alongshore velocities are similar. Inferred, inner-shelf, wave-induced, cross-shore exchange is more important than on the U.S. East Coast. Overall, the coupled ROMS-SWAN model represents well the waves and subtidal circulation dynamics from the midshelf to the surfzone.

    AMER METEOROLOGICAL SOC, Jun. 2015, JOURNAL OF PHYSICAL OCEANOGRAPHY, 45 (6), 1464 - 1490, English

    [Refereed]

    Scientific journal

  • Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2015

    Baba, Y, Mizutani, H, Kubo, T, Uchiyama, Y, Mori, N, Watanabe, Y, Yamada, T, Saruwatari, A, Otsuka, J, Ninomiya, J

    This paper shows some results of a field observation carried out in the summer of 2015. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. In the summer in 2015, no typhoon approached around the observation site, and the high wave and strong wind conditions have not been captured during the observation. Several short-term rainfalls due to front and low pressure occurred, and it is reported that local areas in Shirahama town and neighboring towns suffered some damages with windblasts from late August to early September. It is found in the observation results of water temperature that the temporal variations of water temperature have a period of 3 to 6 days in the deeper layers like 20m deep and 30m deep. The cyclical fluctuation of water temperature at 30m deep has opposite phase to the fluctuation of salinity. This result means that low temperature and high salinity water approaches to the observation site periodically and that some influences of the water mass of the open sea exist.

    京都大学防災研究所, 2015, Annuals of Disas. Prev. Res. Inst., Kyoto Univ., 59 (59), 431 - 437, Japanese

    Research institution

  • Uchiyama, Y, Yamanishi, T, Tsumune, D, Miyazawa, Y

    Fluvial discharge from the rivers is viewed as a missing piece for the inventory of the radionuclides in the ocean during the accident at the Fukushima Daiichi Nuclear Power Plant. The land-derived input introduces a time lag behind the direct release through hydrological process because these radionuclides mostly attach to suspended particles (sediments) that are transported quite differently to the dissolved matter in the ocean. We therefore develop a regional sediment transport model consisting of a multi-class non-cohesive sediment transport module, a wave-enhanced bed boundary layer model and a stratigraphy model proposed by Blaas et al. (2007) based on ROMS.

    Japan Society of Civil Engineers, Nov. 2014, J. JSCE, Ser.B2, Coastal Engineering, 70 (2), 571 - 575, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Miyazaki, D, Kanki, R, Miyazawa, Y

    In Japan Sea, effects of submesoscale dynamics on the mean structure, eddies, etc. have not been fully understood yet. Towards a rigorous submesoscale Japan Sea modeling, a detailed oceanic downscaling experiment is conducted with a double nested ROMS at horizontal resolutions of 3 km (ROMS-L1) and 1 km (L2), forced by the assimilative JCOPE2 at 1/12 deg. as the lateral boundary condition. The results from ROMS-L1, L2 and JCOPE2 are compared to the observation and satellite altimetry dataset to show a good agreement with an appropriate parameter choice. Submesoscale eddies are quite active in the southern half of Japan Sea, leading to enhancement of prevailing Tsushima and Liman Currents.

    Japan Society of Civil Engineers, Nov. 2014, J. JSCE, Ser.B2, Coastal Engineering, 70 (2), 451 - 455, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Matsuyama, M, Kamidaira, Y

    The ocean absorbs about 1/3 of the anthropogenic CO2 released to the atmosphere. As more CO2 accumulates in the ocean, the oceanic pH decreases, leading to ocean acidification. In order to better understand the carbon cycle in the ocean and associated long-term pH variation, we estimate CO2 exchange flux at the sea surface in the Pacific Ocean with the empirical method proposed by Sugimoto et al. (2012) exploiting the publically available oceanic dataset. The oceanic CO2, the air-sea CO2 flux, and pH are successfully evaluated for the Pacific Ocean from 1985 through 2008. The pH and CO2 absorption relation is then argued along with climatological influences during the ENSO events.

    Japan Society of Civil Engineers, Nov. 2014, J. JSCE, Ser.B2, Coastal Engineering, 70 (2), 1286 - 1290, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Matsukawa, D, Kanki, R, Baba, Y, Mori, N, Mizutami, H, Watanabe, Y, Otsuka, J, Yamada, T, Saruwatari, A, Ninomiya, J

    Tanabe bay is a small embayment connected directly to the Pacific Ocean to the south, whereas frequently suffers from harmful algal blooms due to sewage effluent and the local aquaculture industry. For preserving the ecosystem in the bay, it is necessary to understand an oceanic structure in the bay along with water exchange at the bay entrance. We thus conduct a comprehensive investigation consisting of a shipboard measurement, a season-long platform observation, and a triply nested high-resolution ocean modeling. The water exchange at the bay mouth is largely affected by semi-diurnal tidal currents and episodic subtidal intrusion of the offshore water controlled by mesoscale circulations.

    Japan Society of Civil Engineers, Nov. 2014, J. JSCE, Ser.B2, Coastal Engineering, 70 (2), 446 - 450, Japanese

    [Refereed]

    Scientific journal

  • Kaida, H, Uchiyama, Y

    Effects of two-way wave-current interaction (WCI) on the surfzone-inner shelf circulations affected by submesoscale eddies and unsteady littoral currents are investigated with the ROMS-WEC model (Uchiyama et al., 2010) coupled tightly with a spectrum-peak wave model to account for both wave effects on currents (WEC) and current effects on waves (CEW) (e.g., Uchiyama et al., 2009). Eddy activity around the outer edge of the surfzone is enhanced when CEW is considered. The key mechanism to induce the surfzone-inner shelf dynamical interaction and enhancement of offshore eddy activity is considered to be CEW that weakens the offshore component of the littoral currents. In turn,offshore eddy activity is attenuated by WEC, demonstrating that WCI plays an essential role not only in the sufzone but also in the shelf region.

    Japan Society of Civil Engineers, Nov. 2014, J. JSCE, Ser.B2, Coastal Engineering, 70 (2), 71 - 75, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Kosako, T, Nishii, T, Mitarai, S

    Connectivity evaluates stochastic processes of larval dispersal due to chaotic coastal circulations (e.g., Mitarai et al., 2009). In the present study, we quantify Lagrangian PDFs and connectivity using many Lagrangian particles released from 140 source sites in the modeled SIS circulation field in a double-nested, high-resolution ROMS configuration (Uchiyama et al., 2012). In winter, the fraction of particles transported to another region is about less than 40% except for both the channels, suggesting that particles largely remain in the release region. The regional connectivity is correlated with the seasonal variation of the mass fluxes at the straights between two neighboring regions. Particles released from Harima-Nada, representing larvae of marbled sole, are mainly transported towards the northern shore of Shodo Island, while particles arriving there originate mostly from the western shore of Harima-Nada.

    Japan Society of Civil Engineers, Nov. 2014, J. JSCE, Ser.B2, Coastal Engineering, 70 (2), 1076 - 1080, Japanese

    [Refereed]

    Scientific journal

  • On tridimensional rip current modeling

    Marchesiello, P, Benshila, R, Almar, R, Uchiyama, Y, McWilliams, J, Shchepetkin, A

    IAHR, Sep. 2014, Proc. 19th IAHR-APD Congress 2014, 7 pp., English

    [Refereed]

    International conference proceedings

  • Effects of the submesoscale anticyclonic eddies induced by Kuroshio in East China Sea

    Kamidaira, Y, Uchiyama, Y, Mitarai, S, Sakagami, T

    ISOPE, Jun. 2014, Proc. 24th International Ocean and Polar Engineering Conference, 5 pp., English

    [Refereed]

    International conference proceedings

  • Coastal dispersal of urban treated wastewater in semi-enclosed estuaries

    Uchiyama, Y, Kanki, R, Nakayama, A

    ISOPE, Jun. 2014, Proc. 24th International Ocean and Polar Engineering Conference, 4 pp., English

    [Refereed]

    International conference proceedings

  • Yusuke Uchiyama, Eileen Y. Idica, James C. McWilliams, Keith D. Stolzenbach

    The dispersal and dilution of urban wastewater effluents from offshore, subsurface outfalls is simulated with a comprehensive circulation model with downscaling in nested grid configurations for San Pedro and Santa Monica Bays in Southern California during Fall of 2006. The circulation is comprised of mean persistent currents, mesoscale and submesoscale eddies, and tides. Effluent volume inflow rates at Huntington Beach and Hyperion are specified, and both their present outfall locations and alternative nearshore diversion sites are assessed. The effluent tracer concentration fields are highly intermittent mainly due to eddy currents, and their probability distribution functions have long tails of high concentration. The dilution rate is controlled by submesoscale stirring and straining in tracer filaments. The dominant dispersal pattern is alongshore in both directions, approximately along isobaths, over distances of more than 10 km before dilution takes over. The current outfall locations mostly keep the effluent below the surface and away from the shore, as intended, but the nearshore diversions do not. (C) 2014 Elsevier Ltd. All rights reserved.

    PERGAMON-ELSEVIER SCIENCE LTD, Mar. 2014, CONTINENTAL SHELF RESEARCH, 76, 36 - 52, English

    [Refereed]

    Scientific journal

  • Phan, T.N.M, Wells, J.C, Uchiyama, Y, Ishii, S, Bonner, J.S, Islam, M.S, Kirkey, W.D

    Principal Component Analysis (PCA) is proposed on long-beam velocities of Horizontal Acoustic Doppler Current Profiler (HADCP) to extract flow dynamics in near-bank regions and check simulation results, particularly Regional Ocean Modeling System (ROMS) performed for the Hudson River estuary (New York, USA). We here analyzed data measured by Horizontal Acoustic Doppler Current Profiler (HADCP) at West Point, on the inner bank downstream of a bend. Results show an agreement between HADCP and ROMS in the first mode, which capture more than 97% energy of the turbulent flow measured along three HADCP beams. In addition, there appears an asymmetry between ebb and flood in the second temporal coefficient. Low-order PCA coefficients of HADCP and ROMS have fluctuation in ebb tide which may be associated with topographically-generated eddies. Tidal effect is found in lower order temporal coefficients and their spectra.

    JSCE, Mar. 2014, Annual Journal of Hydraulic Eng., 70 (4), 73 - 78, English

    [Refereed]

    Scientific journal

  • Wave-current interaction in dynamics of batoropic nearshore current system

    Hideki Kaida, Yusuke Uchiyama

    JSCE, Jan. 2014, J. JSCE, Ser.B2, Coastal Engineering, 70 (1), 1 - 14, Japanese

    [Refereed]

    Scientific journal

  • Baba, Y, Mizutani, H, Kubo, T, Uchiyama, Y, Mori, N, Watanabe, Y, Otsuka, J, Yamada, T, Saruwatari, A, Ninomiya, J

    公益社団法人 土木学会, 2014, J. JSCE, Ser.B2, Coastal Engineering, 70 (2), I_476 - I_480, Japanese

    [Refereed]

    Scientific journal

  • Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2014

    Baba, Y, Mizutani, H, Kubo, T, Uchiyama, Y, Mori, N, Watanabe, Y, Yamada, T, Saruwatari, A, Otsuka, J, Ninomiya. J

    This paper shows some results of a field observation carried out in the summer of 2014. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity and dissolved oxygen level observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. In the summer in 2014, a total of 4 typhoons (No.11, No.12, No.18 and No.19) approached to the Kii peninsula, and the high wave and strong wind conditons due to 2 typhoons (No.18 and No.19) have been captured during the observation. When the typhoons passed around the observation site, the high wave and strong wind occurred. However, the observation data of 2014 doesn't have clear shift of water temperature and salinity like the one by the typhoon No.18 in 2013. On the other hand, it is repeatedly found in the observed data that the reduction of water temperature and the increase of salinity happened simultaneously. This result indicates that the water temperature and the salinity around the observation site have some influence of the water mass of the open sea.

    京都大学防災研究所, 2014, Annuals of Disas. Prev. Res. Inst., Kyoto Univ., (58), 315 - 320, Japanese

    Research institution

  • Uchiyama, Y, Kamidaira, Y, Mitarai, S, Sakagami, T

    土木学会, Nov. 2013, J. JSCE, Ser.B2, Coastal Engineering, 69 (2), 471 - 475, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Miyazaki, D, Kaida, H

    Nov. 2013, J. JSCE, Ser.B2, Coastal Engineering, 69 (2), 521 - 525, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Yananishi, T, Tsumune, D, Miyazawa, Y, Ishii, T

    Nov. 2013, J. JSCE, Ser.B2, Coastal Engineering, 69 (2), 1051 - 1055, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Ishii, S, Miyazawa, Y

    土木学会, Nov. 2013, J. JSCE, Ser.B2, Coastal Engineering, 69 (2), 456 - 460, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Kanki, R, Nakayama, A

    土木学会, Nov. 2013, J. JSCE, Ser.B2, Coastal Engineering, 69 (2), 1056 - 1060, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Nishii, T, Mori, N, Baba, Y

    土木学会, Nov. 2013, J. JSCE, Ser.B2, Coastal Engineering, 69 (2), 481 - 485, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Kaida, H, McWilliams, J

    土木学会, Nov. 2013, J. JSCE, Ser.B2, Coastal Engineering, 69 (2), 56 - 60, Japanese

    [Refereed]

    Scientific journal

  • Leonel Romero, Yusuke Uchiyama, J. Carter Ohlmann, James C. Mcwilliams, David A. Siegel

    Knowledge of horizontal relative dispersion in nearshore oceans is important for many applications including the transport and fate of pollutants and the dynamics of nearshore ecosystems. Two-particle dispersion statistics are calculated from millions of synthetic particle trajectories from high-resolution numerical simulations of the Southern California Bight. The model horizontal resolution of 250 m allows the investigation of the two-particle dispersion, with an initial pair separation of 500 m. The relative dispersion is characterized with respect to the coastal geometry, bathymetry, eddy kinetic energy, and the relative magnitudes of strain and vorticity. Dispersion is dominated by the submesoscale, not by tides. In general, headlands are more energetic and dispersive than bays. Relative diffusivity estimates are smaller and more anisotropic close to shore. Farther from shore, the relative diffusivity increases and becomes less anisotropic, approaching isotropy similar to 10 km from the coast. The degree of anisotropy of the relative diffusivity is qualitatively consistent with that for eddy kinetic energy. The total relative diffusivity as a function of pair separation distance R is on average proportional to R-5/4. Additional Lagrangian experiments at higher horizontal numerical resolution confirmed the robustness of these results. Structures of large vorticity are preferably elongated and aligned with the coastline nearshore, which may limit cross-shelf dispersion. The results provide useful information for the design of subgrid-scale mixing parameterizations as well as quantifying the transport and dispersal of dissolved pollutants and biological propagules.

    AMER METEOROLOGICAL SOC, Sep. 2013, JOURNAL OF PHYSICAL OCEANOGRAPHY, 43 (9), 1862 - 1879, English

    [Refereed]

    Scientific journal

  • Field measurement at Tanabe-Nakashima observation tower in the summer of 2012

    Y. Baba, T. Kubo, Y. Uchiyama, N. Mori

    Disaster Prevention Research Inst., Kyoto Univ., Jun. 2013, Annuals of Disaster Prevention Research Inst., Kyoto Univ., (56B), 441 - 447, Japanese

    Research institution

  • Wave-current interaction in formation of RIP channel system

    Y. Uchiyama, H. Kaida, D. Miyazaki

    © APAC 2013.All rights reserved. Current effect on waves (CEW) is examined for formation of a rip channel system with a barotropic modeling framework based on Uchiyama et al. (2009). The model consists of an Eulerian phase-averaged shallow water equation with a vortex-force formalism, WKB ray equations for spectrum-peak waves, and a bed evolution equation with the Soulsby-Van Rijn's total sediment flux prescription. CEW acts on reducing the offshore extent of seaward rip currents through wave refraction on the currents, leading to modifying the budget of sediment flux and associated surf-zone topography. Inclusion of CEW results in shoaling rip channels, deepening offshore mounds, and elongating alongshore spacing of rip channels with normal incidence of offshore waves.

    2013, Proceedings of the 7th International Conference on Asian and Pacific Coasts, APAC 2013, 173 - 179, English

    [Refereed]

    International conference proceedings

  • Field Observations at an Offshore Observation Tower during the Typhoon Seasons

    Yasuyuki Baba, Teruhiro Kubo, Yusuke Uchiyama, Naoto Kihara, Nobuhito Mori, Yasunori Muto, Takayuki Suzuki

    This paper shows some results of intensive field observations carried out in the summer seasons since 2009. The intensive field observations have been conducted at the observation tower of Shirahama Oceanographic Observatory (SOO), DPRI, Kyoto University. The observation tower of SOO is an offshore platform for the oceanographic and meteorological observation and it is located at the bay mouth of Tanabe bay, the southwestern part of Kii Penisula, Japan. One of the aims of the observations is field data measurements to comprehend the vertical mixing process due to wind and wind wave. During the observations, five typhoons (Melor in 2009, Ma-on, Talas and Roke in 2011 and Jelawat in 2012) hit the Kii peninsula. Three of them (Melor, Roke and Jelawat) passed along the southern coast of Japan and they have similar tracks around the Kii peninsula.. Only Talas in 2011 passed across the main island of Japan and reached the Sea of Japan. In the observations, the vertical profiles of currents and water temperature have been measured as well as wind and wave conditions. The main results are as follows: Wind and wave conditions have common characteristics like the temporal variation of wave period the incidence of high wave peak even though these conditions are affected by the typhoon tracks. The temporal variations of water temperature have also similar trends when the typhoons come close to the observation site, however, the vertical profiles of water temperature before and after the typhoon coming have big difference. The observed results underline the needs for the continuous observation activities and multidimensional data analysis combined with numerical simulations in order to investigate the mixing process under stormy conditions.

    TSINGHUA UNIV, 2013, PROCEEDINGS OF THE 35TH IAHR WORLD CONGRESS, VOLS III AND IV, English

    [Refereed]

    International conference proceedings

  • Field Measurements at Tanabe-Nakashima Observation Tower in the Summer of 2013

    Y. Baba, Mizutani, H, T. Kubo, Y. Uchiyama, N. Mori, Watanabe, Y, Yamada, T, Saruwatari, A, Otsuka, J

    This paper shows some results of a field observation carried out in the summer of 2013. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity and dissolved oxygen level observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. During the observation, one typhoon (No.18, MAN-YI) approached to the Kii peninsula. When the typhoon passed around the observation site, the vertical mixing develops well, and water temperature at all measurement points show almost uniform distributions. It is also found during the typhoon passing that coastal upwelling through the Ekman transport happened clearly due to continuous southward wind. An EOF analysis decomposes the water temperature variation during the typhoon passing into 1) the increase and decease of water temperature and 2) the magnitude of the temperature difference in the vertical direction.

    Disaster Prevention Research Inst., Kyoto Univ., 2013, Annuals of Disaster Prevention Research Inst., Kyoto Univ., (57), 455 - 461, Japanese

    Research institution

  • Uchiyama, Y, Kaida, H

    土木学会, Nov. 2012, J. JSCE, Ser.B2, Coastal Engineering, Vol.68 (2), I_36 - I_40, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Ishii, T, Tsumune, D, Miyazawa, Y

    土木学会, Nov. 2012, J. JSCE, Ser.B2, Coastal Engineering, Vol.68 (2), I_931 - I_935, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Kuriyama, T, Miyazawa, Y

    土木学会, Nov. 2012, J. JSCE, Ser.B2, Coastal Engineering, Vol.68 (2), I_441 - I_445, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Nishii, T, McWilliams, J

    土木学会, Nov. 2012, J. JSCE, Ser.B2, Coastal Engineering, Vol.68 (2), I_426 - I_430, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Ishii, S, Miyazawa, Y

    土木学会, Nov. 2012, J. JSCE, Ser.B2, Coastal Engineering, Vol.68 (2), I_436 - I_440, Japanese

    [Refereed]

    Scientific journal

  • M. C. Buijsman, Y. Uchiyama, J. C. McWilliams, C. R. Hill-Lindsay

    The Regional Oceanic Modeling System (ROMS) is applied in a nested configuration with realistic forcing to the Southern California Bight (SCB) to analyze the variability in semidiurnal internal wave generation and propagation. The SCB has a complex topography with supercritical slopes that generate linear internal waves at the forcing frequency. The model predicts the observed barotropic and baroclinic tides reasonably well, although the observed baroclinic tides feature slightly larger amplitudes. The strongest semidiurnal barotropic to baroclinic energy conversion occurs on a steep sill slope of the 1900-m-deep Santa Cruz Basin. This causes a forced, near-resonant, semidiurnal Poincare wave that rotates clockwise in the basin and is of the first mode along the radial, azimuthal, and vertical directions. The associated tidal-mean, depth-integrated energy fluxes and isotherm oscillation amplitudes in the basin reach maximum values of about 5 kW m(-1) and 100 m and are strongly modulated by the spring-neap cycle. Most energy is locally dissipated, and only 10% escapes the basin. The baroclinic energy in the remaining basins is orders of magnitudes smaller. High-resolution coastal models are important in locating overlooked mixing hotspots such as the Santa Cruz Basin. These mixing hotspots may be important for ocean mixing and the overturning circulation.

    AMER METEOROLOGICAL SOC, Jan. 2012, JOURNAL OF PHYSICAL OCEANOGRAPHY, 42 (1), 62 - 77, English

    [Refereed]

    Scientific journal

  • Liang, J.-H, McWilliams, J.C, Kurian, J, Colas, F, Wang, P, Uchiyama, Y

    2012, Journal of Geophysical Research - Oceans, 117 (C7), 7003 - 7003

    [Refereed]

    Scientific journal

  • Uchiyama, Y, McWilliams, J

    Nov. 2011, J. JSCE, Ser.B2, Coastal Engineering, Vol.67, No.2, 96-100., Japanese

    [Refereed]

    Scientific journal

  • B. Weir, Y. Uchiyama, E. M. Lane, J. M. Restrepo, J. C. McWilliams

    We use the vortex force formalism to analyze the effect of rip currents on their own wave forcing. The vortex force formalism allows us to decompose the wave forcing into the nonconservative flux of momentum due to wave breaking and the conservative vortex force. Following Yu and Slinn (2003), we consider rip currents initially generated by alongshore variation of wave breaking due to a perturbation of a barred bottom topography. This variation is reduced in magnitude by two current effects on waves: wave ray bending and the flux of wave energy by currents. We compute the change in wave energy caused by these two effects on their own and use this to show that their relative magnitude scales with the square of the ratio of the length to width of the rip current. Both effects increase the wave height over the channels of the longshore bar, which leads to more wave breaking and counterbalances its longshore variation due to bottom refraction. In comparison to wave breaking, the change in the vortex force is negligible. Next, we show how the reduction in wave breaking is similar to an enhanced bottom friction. We then analyze the dependence of this relationship on the breaking parameterization, angle of incidence of the waves, and bottom drag law.

    AMER GEOPHYSICAL UNION, May 2011, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 116 (C5), 1 - 16, English

    [Refereed]

    Scientific journal

  • Yusuke Uchiyama, James C. McWilliams, Alexander F. Shchepetkin

    A vortex-force formalism for the interaction of surface gravity waves and currents is implemented in a three-dimensional (3D), terrain-following, hydrostatic, oceanic circulation model (Regional Oceanic Modeling System: ROMS; Shchepetkin and McWilliams, 2005). Eulerian wave-averaged current equations for mass, momentum, and tracers are included in ROMS based on an asymptotic theory by McWilliams et al. (2004) plus non-conservative wave effects due to wave breaking, associated surface roller waves, bottom streaming, and wave-enhanced vertical mixing and bottom drag especially for coastal and nearshore applications. The currents are coupled with a spectrum-peak WKB wave-refraction model that includes the effect of currents on waves, or, alternatively, a spectrum-resolving wave model (e.g., SWAN) is used. The coupled system is applied to the nearshore surf zone during the DUCK94 field measurement campaign. Model results are compared to the observations and effects of parameter choices are investigated with emphasis on simulating and interpreting the vertical profiles for alongshore and cross-shore currents. The model is further compared to another ROMS-based 3D coupled model by Warner et al. (2008) with depth-dependent radiation stresses on a plane beach. In both tests the present model manifests an onshore surface flow and compensating offshore near-bed undertow near the shoreline and around the breaking point. In contrast, the radiation-stress prescription yields significantly weaker vertical shear. The currents' cross-shore and vertical structure is significantly shaped by the wave effects of near-surface breaker acceleration, vertical component of vortex force, and wave-enhanced pressure force and bottom drag. (C) 2010 Elsevier Ltd. All rights reserved.

    ELSEVIER SCI LTD, 2010, OCEAN MODELLING, 34 (1-2), 16 - 35, English

    [Refereed]

    Scientific journal

  • Changming Dong, Timothy Mavor, Francesco Nencioli, Songnian Jiang, Yusuke Uchiyama, James C. McWilliams, Tommy Dickey, Michael Ondrusek, Hongchun Zhang, Dennis K. Clark

    A young cold core cyclonic eddy displaying a significant increase in surface chlorophyll was observed offshore Lanai Island, Hawai'i, where the Marine Optical Buoy (MOBY) is located. During one of its deployments, MOBY broke free from its mooring. In the course of its 3-day free drifting period, MOBY followed a cyclonic eddy, which is manifested by satellite remote sensing data, chlorophyll data from Moderate Resolution Imaging Spectroradiometer, and sea surface temperature (SST) from a Geostationary Operational Environmental Satellite. The time series of the SST show that the cold core eddy was in a formative stage. It existed as a stand-alone eddy for about 9 days before it merged with cold water south of Oahu Island. A high-resolution numerical model simulation reproduces similar eddies in terms of location, size, and intensity. An eddy detection algorithm is described and applied to locate and track the modeled eddies. The results demonstrate that mesoscale and submesoscale eddies are frequently generated on and pass through the lee side of Lanai Island and the statistical analysis quantifies the general features of eddies in the area.

    AMER GEOPHYSICAL UNION, Oct. 2009, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 114 (C10), 10008, English

    [Refereed]

    Scientific journal

  • Yusuke Uchiyama, James C. McWilliams, Juan M. Restrepo

    We examine wave-current interactions in littoral current shear instabilities above a single-barred beach using a fully coupled wave and barotropic current model based on the multiscale asymptotic theory derived by McWilliams et al. (2004). This Eulerian wave-averaged model captures wave effects on currents (WEC) in a manner that leads to simple interpretations. The dynamically conservative WEC are the vortex force and material transport by Stokes drift and the sea level adjustment by wave set-down and setup. In the setting considered here there are also important current effects on the waves (CEW): induction of a Doppler shift by currents and surface elevation variation in the wave dispersion relation. Nonconservative effects, due to wave breaking and bottom drag, also play a prominent role in generating and equilibrating the mean alongshore current, consistent with prior studies. High bottom drag stabilizes the currents, while a drag reduction below a critical threshold value leads to shear instability with nearly periodic, alongshore-fluctuating eddies. An even smaller bottom drag yields irregular eddy motions with intermittent offshore eruption of vortex pairs from the meandering alongshore current. Several alternative parameterizations of the bottom drag are contrasted here. Including CEW in the model leads to a delay in the onset of the instability, a suppression of fluctuations in cross-shore velocity and lateral Reynolds stress, and an enhancement of the mean alongshore velocity. The WEC increase the Reynolds stress in the offshore region, and the conservative vortex force and mean advection are comparable in magnitude to the breaking acceleration and bottom drag. Conversely, the CEW reduce the Reynolds stress and attenuate the breaking acceleration through refractive focusing by current shear. Overall, the WEC enhance the instantaneous cross-shore momentum flux to induce more energetic eddy motions and retard the mean alongshore current, while the CEW stabilize the fluctuations and help maintain a strong mean current.

    AMER GEOPHYSICAL UNION, Jun. 2009, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 114 (C6), 6021, English

    [Refereed]

    Scientific journal

  • Yusuke Uchiyama, James C. McWilliams

    [1] Oceanic infragravity waves are investigated as a possible source of seismic free oscillations, often referred to as the `` hum'' of the Earth, using a numerical model of depth- independent, nondispersive, long- wave dynamics with a forcing from nonlinear interactions among the primary wind waves ( including swell). Because of near- resonant amplification, the structure of the primary- wave forcing field in shallow water, and an edge- trapping mechanism, infragravity waves are excited very effectively near the coasts. Deep- water infragravity waves are significantly influenced both by offshore leakage and propagation of the coastally generated free waves and by deep- water primary- wave forcing. With the inclusion of `` mesoscale'' variability on top of the more slowly varying primary waves generated in synoptic storms, the deep- water infragravity waves are found to have an amplitude on the order of a millimeter in height, which is consistent with field observations and considered to be sufficient to account for local hum excitation in the middle of the basin.

    AMER GEOPHYSICAL UNION, Jul. 2008, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 113 (C7), 7029, English

    [Refereed]

    Scientific journal

  • Yusuke Uchiyama

    Hydrodynamics, sediment suspension, and morphological response on an estuarine intertidal sand flat in Tokyo Bay, Japan, are examined through a field experiment performed for 16 days in winter 2000 and using a bathymetry data set based on a 6-year series of surveys. Topography of the sandy flat was found to fluctuate by approximately 8 cm during the deployment, while the long-term accumulation rate is estimated with the surveyed bathymetries to be only 3.8 cm/y. Cross-spectral analysis of the measured data indicates that on the sandy tidal flat, semidiurnal or sho erter Period fluctuations in current velocity are mostly attributed to semidiurnal tides and waves, whereas wind above the generally drives diurnal or longer-period fluctuations. The field data also confirm that suspended sediment concentrations were highly correlated with bed shear stress, which is generated by combination of tidal current, wind-induced current, and wind waves. Episodic erosion is observed on the sandy flat with high turbidities on ebbing phases. Erosion evidently occurs at phases between the high slack and the mean tidal levels during ebb flows when combined tidal, wind-driven, and wave-driven currents are maximized.

    COASTAL EDUCATION & RESEARCH FOUNDATION, Jul. 2007, JOURNAL OF COASTAL RESEARCH, 23 (4), 1015 - 1027, English

    [Refereed]

    Scientific journal

  • 桑江朝比古, 神尾光一郎, 井上徹教, 三好英一, UCHIYAMA YUSUKE

    堆積物による酸素消費と生成は, これまで底生閉鎖系システム内の酸素濃度変化を追跡する方法で測定されていた. しかし, 従来法では外力条件や間隙水の移流を再現した測定ができず, その精度には疑問があった. 本研究では, ADV・酸素微小電極・渦相関法を用いることにより, 従来法とはまったく異なる測定手法を新たに開発し, 高精度な測定に成功した. 透水性のある砂質堆積物の酸素消費速度を従来法で測定した結果, 最大でも渦相関法の23%であったことから, 従来法では速度を著しく過小評価する可能性が高いことがわかった. 渦相関法は従来法の欠点が克服され適用範囲も広いことから, 今後の標準法になり得ることが確認された.

    土木学会, 2006, 海岸工学論文集, 53, 1411 - 1415, Japanese

    [Refereed]

    Scientific journal

  • T Kuwae, K Kamio, T Inoue, E Miyoshi, Y Uchiyama

    High temporal-resolution fluctuations in oxygen concentration and vertical velocity were measured over an intertidal sandflat (water depth < 69 cm) using an oxygen microelectrode and an acoustic Doppler velocimeter, in order to estimate oxygen flux across the sediment-water interface using the eddy-correlation method. The effect of flux estimate procedures, including noise removal and extraction of fluctuating components, was investigated. The estimated oxygen effluxes from the sediment ranged from -3.2 to 6.6 mmol O-2 m(-2) h(-1) in the light and from -14.5 to -6.6 mmol O-2 m(-2) h(-1) in the dark. The oxygen-uptake fluxes in the dark were markedly higher than those measured by a conventional enclosure technique. High-frequency turbulence and/or noise (> 5 Hz) observed in the vertical velocity and oxygen concentration data made little contribution to the total oxygen flux (0 to 7 %). However, trends (steady change over a longer time scale) caused significant artifacts in the estimated fluxes for several cases. Thus, removal of trends from raw time-series data is recommended. The co-spectrum of the fluctuating components of vertical velocity and oxygen concentration revealed that the oxygen flux at a frequency band between 0.3 and 1.4 Hz (at a period from 0.7 to 3.3 s) was a major contributor to the total oxygen flux. This frequency was consistent with the dominant frequency of vertical velocity, indicating that transport and exchange of porewater and overlying water by wind-induced waves may be crucial processes to dissolved oxygen flux between permeable sandy sediments and shallow waters.

    INTER-RESEARCH, 2006, MARINE ECOLOGY PROGRESS SERIES, 307, 59 - 68, English

    [Refereed]

    Scientific journal

  • UCHIYAMA YUSUKE, 中野博文, 黒坂正和, 山脇秀仁, 柳島慎一, 栗山善昭

    干出・冠水を繰り返す自然砂質干潟海域において, 流速の周波数特性および平均的な鉛直分布構造に関する現地観測を実施した. スペクトル解析, CEOF解析により, 干潟の水理特性, 特に波-流れ共存場としての海底境界層の力学特性を調べた. その結果, 基本モードとしては潮流に対応したbarotropic成分が卓越するが, 波や風による高次モードの影響も無視し得ないこと, そのため対数則速度分布からの逸脱が生じ, 鉛直方向に流向が回転することが分かった. 一方, 瞬間的な流速変動に対しては波動成分の寄与が圧倒的に大きく, 次いで乱流成分が卓越していた.

    土木学会, 2005, 海岸工学論文集, 52, 81 - 85, Japanese

    [Refereed]

    Scientific journal

  • Modeling three-dimensional cohesive sediment transport and associated morphological variation in estuarine intertidal mudflats

    Uchiyama Yusuke

    港湾空港技術研究所, 2005, Report of Port and Airport Research Institute, 44 (1), 3 - 21, English

    [Refereed]

    Research institution

  • UCHIYAMA YUSUKE

    土木学会, 2004, 海岸工学論文集, 51 (1), 351 - 355, Japanese

    [Refereed]

    Scientific journal

  • Wetting and drying scheme for POM and its application to San Francisco Bay

    Uchiyama Yusuke

    Taylor & Francis Group, London, UK, 2004, Hydrodynamics VI - Theory and Application, (eds) L. Cheng and K. Yeow, 293 - 299, English

    [Refereed]

    International conference proceedings

  • Modeling wetting and drying scheme based on an extended logarithmic law for a three-dimensional sigma-coordinate coastal ocean model, Rep. Port and Airport Res. Inst., Yokosuka, Japan, Vol.43, No.4, pp.3-21.

    Uchiyama Yusuke

    港湾空港技術研究所, 2004, Report of Port and Airport Research Institute, 43 (4), 3 - 21, English

    [Refereed]

    Research institution

  • 栗山善昭, UCHIYAMA YUSUKE, 中村聡志, 永江友和

    土木学会, 2003, 土木学会論文集, (726), 109 - 120, Japanese

    [Refereed]

    Scientific journal

  • UCHIYAMA YUSUKE, 栗山善昭

    土木学会, 2003, 土木学会論文集, (747), 135 - 153, Japanese

    [Refereed]

    Scientific journal

  • Medium-term bathymetric change around jetties at Imagireguchi Inlet, Japan

    Kuriyama Y, Uchiyama Yusuke, Nakamura S, Nagae T

    CERF, 2003, Journal of Coastal Research, 33, 223 - 236, English

    [Refereed]

    Scientific journal

  • Complex principal component analysis of medium-term nearshore geomorphology at North Sendai Coast, Japan

    Uchiyama Yusuke, Kuriyama Y

    American Sciety for Civil Engineers, Portland, OR, USA, 2003, Proc. Coastal Structures 2003, 1176 - 1188, English

    [Refereed]

    International conference proceedings

  • 複素主成分分析を用いた仙台湾蒲生干潟前面海浜地形の中期変動特性の解析

    UCHIYAMA YUSUKE, 栗山善昭

    港湾空港技術研究所, 2002, 港湾空港技術研究所報告, 41 (2), 3 - 22, Japanese

    [Refereed]

    Research institution

  • 島谷 学, 中瀬浩太, 岩本裕之, 中山哲厳, 月舘真理雄, 星野高士, UCHIYAMA YUSUKE, 灘岡和夫

    土木学会, 2002, 海岸工学論文集, 49, 1161 - 1165, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Nakashima, T, Ueoka, S

    JSCE, 2001, Proc. of Coastal Engineering, 48, 531 - 535, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y

    JSCE, 2001, Journal of Hydraulic, Coastal and Environmental Engineering, 677 (677), 129 - 140, Japanese

    [Refereed]

    Scientific journal

  • 島谷 学, 中瀬浩太, 中山哲厳, 太田雅隆, 月舘真理雄, 星野高士, UCHIYAMA YUSUKE, 灘岡和夫

    土木学会, 2001, 海岸工学論文集, 48, 1156 - 1160, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y

    JSCE, 2001, Journal of Hydraulic, Coastal and Environmental Engineering, 670 (670), 37 - 48, Japanese

    [Refereed]

    Scientific journal

  • 中山哲厳, 槙本一徳, 灘岡和夫, UCHIYAMA YUSUKE, 中瀬浩太, 島谷 学, 星野高士, 月舘真理雄

    土木学会, 2001, 海岸工学論文集, 48, 1161 - 1165, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Kuriyama, Y, Hatano, A

    JSCE, 2001, Proc. of Coastal Engineering, 48, 601 - 605, Japanese

    [Refereed]

    Scientific journal

  • Y Uchiyama, Y Kuriyama, K Katoh

    A short-term field observation was conducted to investigate hydrodynamics, sediment suspension and morphological processes on an intertidal flat. The topography on the tidal flat was found to fluctuate by about 8 cm during two weeks although long-term accumulation rate was estimated to be only about 4 cm/y. Suspended sediment concentrations were highly correlated with bed shear stress due to tidal current, wind-induced current and wave. Episodic erosions were frequently observed with high turbidities, which were caused by relatively high wave and strong current between the high water and the mean water during ebb tide.

    AMER SOC CIVIL ENGINEERS, 2001, COASTAL DYNAMICS '01: PROCEEDINGS, 1038 - 1047, English

    [Refereed]

    International conference proceedings

  • Y Uchiyama, K Nadaoka, P Rolke, K Adachi, H Yagi

    Submarine groundwater discharge (SGWD) and associated nutrient fluxes at Hasaki Beach along the Kashima coast in Japan were investigated through field measurements and numerical simulations. The field data indicate that (1) groundwater has higher concentrations of land-derived nutrients than seawater and river water; (2) microbial activity near the shoreline is likely to induce mineralization, reduction, and oxidation of nitrogen and phosphorus; and (3) in the portion of the aquifer underlying coastal forest, nitrate is appreciably reduced. A numerical model incorporating effects of water table and tidal fluctuations was developed to evaluate SGWD. Assuming that the aquifer consists of homogeneous sandy soil, the simulation results show that the nutrient flux due to SGWD is less than that of Tone River discharge. The nutrient flux via groundwater seepage is considered to be a minor component of primary productivity in the surf zone.

    AMER GEOPHYSICAL UNION, Jun. 2000, WATER RESOURCES RESEARCH, 36 (6), 1467 - 1479, English

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Katoh, K, Kuriyama, Y, Furukawa, K

    JSCE, 2000, Proc. of Coastal Engineering, 47 (1), 521 - 525, Japanese

    [Refereed]

    Scientific journal

  • 東京湾盤洲干潟の短期地形変動特性とそのメカニズムについて

    UCHIYAMA YUSUKE

    港湾技術研究所, 2000, 港湾技術研究所報告, 39 (3), 3 - 18, Japanese

    [Refereed]

    Research institution

  • 栗山善昭, 灘岡和夫, 武若 聡, 岡安章夫, 片山裕之, 森 信人, UCHIYAMA YUSUKE, 中島 剛, 田村仁, 堀口敬洋

    土木学会, 2000, 海岸工学論文集, 47, 231 - 235, Japanese

    [Refereed]

    Scientific journal

  • Formation of longitudinal vortices generated by wind-driven current in the nearshore sea

    Nadaoka K, Uchiyama Yusuke

    IAHR, Yokohama, Japan, 2000, Proc. 4th International Conference on Hydrodynamics, 797 - 802, English

    [Refereed]

    International conference proceedings

  • Uchiyama, Y

    JSCE, 1999, Proc. of Coastal Engineering, 46, 1241 - 1245, Japanese

    [Refereed]

    Scientific journal

  • Numerical analysis on groundwater flow in sandy beaches considering tidal fluctuation and density distribution

    Uchiyama, Y

    -, 1999, Report of Port and Harbour Research Institute, 38 (2), 3 - 27, Japanese

    [Refereed]

    Research institution

  • Uchiyama, Y, Adachi, K, Nadaoka, K, Yagi, H, Rolke, P

    -, 1999, Journal of Hydraulic, Coastal and Environmental Engineering, 635 (635), 127 - 139, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Nadaoka, K, Sezaki, T, Yagi, H

    JSCE, 1998, Journal of Hydraulic, Coastal and Environmental Engineering, 593 (593), 125 - 144, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Nadaoka, K, Horikawa, S

    JSCE, 1998, Proc. of Coastal Engineering, 45, 1051 - 1055, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Rolke, P, Nadaoka, K, Adachi, K, Nakasone, T, Yagi, H

    JSCE, 1998, Proc. of Coastal Engineering, 45, 1076 - 1080, Japanese

    [Refereed]

    Scientific journal

  • Uchiyama, Y, Nadaoka, K, Sezaki, T, Yagi, H

    JSCE, 1997, Proc. of Coastal Engineering, 44, 1071 - 1075, Japanese

    [Refereed]

    Scientific journal

  • Nadaoka, K, Uchiyama, Y

    JSCE, 1997, Proc. of Coastal Engineering, 44, 421 - 425, Japanese

    [Refereed]

    Scientific journal

  • Nadaoka, K, Uchiyama, Y, Higashikawa, K

    JSCE, 1996, Proc. of Coastal Engineering, 43, 1171 - 1175, Japanese

    [Refereed]

    Scientific journal

  • Nadaoka, K, Uchiyama, Y, Yamashita, T

    JSCE, 1996, Journal of Hydraulic, Coastal and Environmental Engineering, (533), 193 - 204, Japanese

    [Refereed]

    Scientific journal

  • Nadaoka, K, Uchiyama, Y, Higashikawa, K

    JSCE, 1996, Proc. of Coastal Engineering, 43, 401 - 405, Japanese

    [Refereed]

    Scientific journal

  • Nadaoka, K, Uchiyama, Y, Sezaki, T

    JSCE, 1996, Proc. of Coastal Engineering, 43, 1101 - 1105, Japanese

    [Refereed]

    Scientific journal

  • 灘岡和夫, UCHIYAMA YUSUKE, 山下哲弘

    Atmospheric environment and related thermal comfort on beaches in summer are significant factors for coastal space design to provide desirable amenity environments. Through a micrometeorological field observation conducted in summer on Makuhaii Beach facing Tokyo Bay, we found that;(1) an internal boundary layer of see breeze was clearly formed on the beach, (2) the beach surface with dry sand has appreciable effects of heating and drying on the surrounding air body, and (3) three physical comfort indices DI, SET* and EHF calculated with the observed data show that the sandy beach and its surroundings provide a highly contrasted spatial structure in thermal comfort.

    土木学会, 1995, 土木計画学研究・論文集, 12, 375 - 381, Japanese

    [Refereed]

    Scientific journal

  • 夏季砂浜海岸の熱収支構造と人体の快適性

    灘岡和夫, UCHIYAMA YUSUKE, 山下哲弘

    土木学会, 1995, 水工学論文集, 39, 189 - 196, Japanese

    [Refereed]

    Scientific journal

  • 福岡捷二, UCHIYAMA YUSUKE

    Discussions have hardly been made on the plan of inhabited district on the so called super levee from the viewpoint of considering flood disaster prevention.
    In this paper, basic ideas of newly inhabited district constructed on the super levee are proposed for accomplishing both functions of dissipating the energy of the flow of overtopping flood water and that of good living circumstances. Severalplans of the arrangement of tall buildings, houses and streets to properly dissipate the energy of overtopping flood flow are shown here according to the policy to haveoverflow water concentrated on streets or not.

    土木学会, 1993, 水工学論文集, 37, 833 - 836, Japanese

    [Refereed]

    Scientific journal

  • 岡地 寛季, 内山 雄介, 水谷 英朗, 山田 朋人, 渡部 靖憲, 猿渡 亜由未, 大塚 淳一, 森 信人, 馬場 康之, 久保 輝広, 二宮 順一

    公益社団法人 土木学会, 2019, 土木学会論文集G(環境), 75 (5), I_41 - I_46, Japanese

    [Refereed]

    Scientific journal

  • 八木 宏, 内山 雄介, 鯉渕 幸生, 日向 博文, 宮崎 早苗, 灘岡 和夫

    Japan Society of Civil Engineers, 1997, 海岸工学論文集, 44, 1076 - 1080, Japanese

  • 八木 宏, 日向 博文, 内山 雄介, 灘岡 和夫

    Japan Society of Civil Engineers, 1999, 海岸工学論文集, 46, 396 - 400, Japanese

  • Kosei Matsushita, Yusuke Uchiyama, Naru Takaura, Taichi Kosako

    Microplastics (MPs) in the ocean have been widely recognized as causing global marine environmental problems. To gain a quantitative and comprehensive understanding of oceanic MP contamination, detailed numerical Lagrangian particle tracking experiments were conducted to evaluate the regional oceanic transport and dispersal of MPs in the South China Sea (SCS) derived from three major rivers, Pearl (China), Mekong (Vietnam), and Pasig (the Philippines), which are known to discharge large amounts of plastic waste into the SCS. As previous field surveys have suggested, MP contamination spreads from the surface to the deeper ocean in the water column, we thus considered three types of MPs: (1) positively buoyant (light) MPs, (2) positively buoyant (light) MPs with random walk diffusion, and (3) full 3-D tracking of non-buoyant MPs that are passively transported by ambient currents. Transport patterns of these MPs from the three rivers clearly showed the intra-annual variability associated with seasonally varying circulations driven by the Asian monsoons in the SCS. Many MPs floating during the prevailing southwest monsoon are transported to the northwest Pacific Ocean and the East China Sea through the Luzon Strait and the Taiwan Strait to form MP hotspots. Non-buoyant MPs are broadly transported from the surface layer to depths of approximately 100 m or deeper, where in situ observations are rare. In addition, the buoyant MPs drifting on the continental shelf originating from southern China tend to be pushed toward the shore and beached by northward wind-induced currents more pronouncedly than the non-buoyant MPs. Therefore, the river-derived MPs to the SCS were found to serve as sources to adjacent basins and oceans, to be distributed not only in the upper layer but also in the abyssal ocean (non-buoyant MPs), and to be transported to the shores (buoyant MPs).

    01 Sep. 2022, Environmental Pollution, 308

    Scientific journal

  • Eiji Masunaga, Yusuke Uchiyama, Xu Zhang, Waku Kimura, Taichi Kosako

    This study investigated submesoscale motions (SMs) and transport over the Izu-Ogasawara Ridge, located off mainland Japan, using a double-nested Regional Oceanic Modeling System (ROMS). Both the Kuroshio and tides largely influence physical processes in this area. The mean and submesoscale kinetic energies (MKE and SKE, respectively) were calculated using a horizontal Gaussian filter. Tidal forcing enhances SKE through Reynolds stress due to mean velocity shear (barotropic conversion); meanwhile, tides suppress the MKE and total kinetic energy. This implies that tidal forcing contributes to energy transfer from large-scale motions to smaller scales, which results in accelerated kinetic energy dissipation. Energy conversion from submesoscale potential energy to SKE (baroclinic conversion) is reduced by tidal forcing. In the summer, SKE is generated by barotropic conversion and suppressed by negative baroclinic conversion. On the other hand, in winter, SKE is enhanced by both barotropic and baroclinic conversions.

    Aug. 2022, Deep-Sea Research Part I: Oceanographic Research Papers, 186

    Scientific journal

  • Kosei Matsushita, Yusuke Uchiyama, Naru Takaura, Taichi Kosako

    Plastic waste is currently one of the biggest global environmental issues. To gain the comprehensive understanding of oceanic microplastic contamination as a key global environmental problem, Lagrangian particle tracking experiments were conducted to evaluate the transport of microplastics (MPs) derived from the four major rivers that have been known to discharge large amounts of plastic waste into the South China Sea (SCS). We carried out two types of experiments using a pre-computed 3D current climatological oceanic model: (1) 2D tracking of MP particles placed at the surface to represent positively buoyant (light) MPs, and (2) fully 3D tracking of neutrally buoyant MP particles that are passively transported by ambient current. The seasonally varying monsoons in the SCS were found to provoke strong seasonal variability in the river-derived MP transport. It was found that a large number of MPs, especially from south China, are transported to the East China Sea in the seasons when the southwesterly monsoon prevails. Moreover, the difference in the density of MPs substantially affects their oceanic transport patterns. The buoyant MPs accumulated near the surface tend to be transported toward nearshore areas by wind-driven Ekman currents.

    21 Dec. 2021, IOP Conference Series: Earth and Environmental Science, 945 (1)

    International conference proceedings

  • Motoki Ubara, Yusuke Uchiyama, Taichi Kosako

    The topography of the seafloor is essential for determining physical phenomena such as ocean currents, favorable habitats for marine organisms, optimal vessel navigation, and so on. Prevailing currents and waves, as well as associated shear stresses acting on the ocean floor, are responsible for the formation of typical topographic features including sea caldrons and sandbanks through erosion of bedrock and sediments and their deposition processes. In the Seto Inland Sea (SIS), the most extensive semi-enclosed estuary in Japan, tidal currents affect pronouncedly the formation of seafloor topographic features; however, they have not been fully studied, particularly from a hydrodynamic viewpoint. This study aims to understand bathymetric formation under the predominance of tidal currents in the SIS. A 3-D high-resolution SIS circulation model based on the JCOPE2-ROMS system in a triple-nested configuration was utilized to examine the detailed hydrodynamic processes for the topography formations. A high correlation between the bottom shear stress and the scour depth of the erosive areas was observed, demonstrating that local tidal forcing has continuously been exerted on the seafloor to erode. A diagnostic sediment budget analysis was then conducted for sediments typical of the SIS, that is, gravel, sand, and clay, using the modeled circulation field. The horizontal divergence of the residual flows indicates consistency between divergence (convergence) and erosion (deposition). The sediment budget model also shows that these sediments are generally transported from deep to shallow areas in eroded terrains to form deposited terrains fringing the eroded terrains, whereas sedimentation tendency differs largely from location to location.

    21 Dec. 2021, IOP Conference Series: Earth and Environmental Science, 945 (1)

    International conference proceedings

  • KOSAKO Taichi, UCHIYAMA Yusuke

    We evaluate sensitivity and robustness of larval dispersal patterns to particle tracking parameters (the number of particles and the particle release depth) and to configurations of circulation model (horizontal resolution and output interval), using a triple-nested, high-resolution Seto Inland Sea (SIS) circulation model coupled with an offline Lagrangian particle tracking model. The optimal number of particles is evaluated 8,000 in inner bays while 12,000 near the mouth. Although the depth of initial particle displacement relevant to vertical migration of spawned larvae is less influential, refinement of lateral grid resolution in the circulation model is essential to realistic larval dispersal patterns due to better representation of complicated flow structures near coastlines and straits. Inclusion of transient tidal forcing is substantial to enhance the robustness, even as residual effects through the daily-averaged circulation field.

    Japan Society of Civil Engineers, 2016, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 72 (2), I_1279 - I_1284, Japanese

MISC

  • 和歌山県田辺湾における海水交換特性の季節変化とその形成メカニズムに関する研究

    Okada, N, Uchiyama, Y

    (公社)瀬戸内海環境保全協会, Mar. 2019, 瀬戸内海, 77, 50–51, Japanese

    [Invited]

    Introduction scientific journal

  • 数式のない土木の数値解析セミナー第23回:海洋環境シミュレーション技術の最先端

    Uchiyama, Y

    土木学会, Nov. 2018, 土木学会誌, 2018年11月号, 46–47, Japanese

    [Invited]

    Introduction scientific journal

  • ディスドロメータを用いた野外飛沫観測

    岡地寛季, 山田朋人, 渡部靖憲, 猿渡亜由未, 大塚淳一, 森信人, 馬場康之, 水谷英朗, 久保輝広, 二宮順一, 内山雄介

    Feb. 2017, 土木学会北海道支部論文報告集(CD-ROM), (73), ROMBUNNO.B‐04, Japanese

  • Okachi Hiroki, Yamada Tomohito, Watanabe Yasunori, Saruwatari Alum, Otuka Junichi, Mori Nobuhito, Baba Yasuyuki, Mizutani Hideaki, Kubo Teruhiko, Ninomiya Junnichi, Uchiyama Yuusuke

    Associated with global warming, the effects of sea level rise are linked to frequency and intensity of storms and other weather events. Previous researches argue that sea spray affects the development of typhoons. This study reports a marine observation on Tanabe bay near Wakayama Prefecture utilizing a measurement instrument called parsivel. Parsivel can detect the diameter of a droplet and the distribution of velocity. In our observation point, we reveal the presence of spray droplets with 1.5mm ~ 5.510mm diameter when typhoon events occurs in 2015. We discuss the relationship between sea spray and wind velocity when storm events occurs.<br>

    水文・水資源学会, 2016, Proceeding of Annual Conference, 29 (0), 35 - 35, Japanese

  • ディスドロメータを用いた飛沫粒径分布の風速及び高度依存性

    岡地寛季, 山田朋人, 渡部靖憲, 猿渡亜由未, 大塚淳一, 馬場康之, 水谷英朗, 久保輝広, 二宮順一, 内山雄介, 森信人

    02 Sep. 2015, 地球環境シンポジウム講演集, 23rd, 149 - 150, Japanese

  • A Coastal Circulation Model for Continental Shelves and Surf Zones

    Uchiyama, Y

    Coastal circulation models applicable to shallow seas ranging from continental shelves to surf zones are essential to add dynamical roles played by surface gravity waves and a multiple nesting technique to account properly for phase-averaged wave forcing and offshore oceanic signals simultaneously. Uchiyama et al(. 2010)developed a ROMS-WEC model based on a multi- scale asympto

    Coastal Oceanography Research Comittee, the Oceanographic Society of Japan, Feb. 2015, Bulletin on Coastal Oceanography, Vol.52 (2), 149 - 158, Japanese

    [Refereed][Invited]

    Introduction scientific journal

  • UCHIYAMA YUSUKE

    日本流体力学会, 2005, ながれ, 24 (1), 57 - 66, Japanese

    [Invited]

    Introduction scientific journal

  • 海辺の快適さと環境要因

    UCHIYAMA YUSUKE

    港湾海岸防災協議会, 2000, 波となぎさ, 144, 69 - 73, Japanese

    [Invited]

    Introduction commerce magazine

  • 陸域起源放射性核種の海域移行定量化を目的とした領域土砂輸送モデルの開発

    山西 琢文, 内山 雄介, 津旨 大輔

    土木学会, Sep. 2014, 地球環境シンポジウム講演集, 22, 211 - 215, Japanese

  • 半閉鎖性海域湾口部における成層期および成層崩壊期の流動構造と海水交換について

    内山雄介, 吉木智軌, 多田拓晃, 馬場康之, 水谷英朗, 久保輝広, 森信人, 猿渡亜由未, 大塚淳一, 二宮順一, 渡部靖憲, 山田朋人

    2016, 土木学会論文集 B2(海岸工学)(Web), 72 (2)

  • Water Temperature Variation at the Mouth of Tanabe Bay during Typhoon Passing

    馬場康之, 水谷英朗, 久保輝広, 内山雄介, 森信人, 渡部靖憲, 大塚淳一, 山田朋人, 猿渡亜由未, 二宮順一

    2014, 土木学会論文集 B2(海岸工学)(Web), 70 (2)

  • 鹿島灘砕波帯における栄養塩濃度の変動要因

    足立 久美子, 内山 雄介, 八木 宏

    31 May 2001, 日本水産工学会学術講演会講演論文集, 13, 135 - 138, Japanese

  • Formation of Streak Structure Generated by Wind-driven Current in Nearshore Region

    NADAOKA Kazuo, UCHIYAMA Yusuke

    Jul. 1997, 年会一般講演, 16, 507 - 508, Japanese

  • Field Observation of Shallow Water Environments in Summer on Sandy Beach in a Bay

    NADAOKA Kazuo, UCHIYAMA Yusuke, SEZAKI Tomoyuki

    Jul. 1996, 年会一般講演, 15, 445 - 446, Japanese

Books etc

  • ラングミュア循環の物理 – 沿岸域への影響:砕波帯周辺で生じる3次元組織渦構造

    内山雄介

    Contributor, 沿岸域への影響:砕波帯周辺で生じる3次元組織渦構造, 月間海洋, Vol. 51, No. 8, 海洋出版, pp. 406–412., Aug. 2019

  • Surface gravity and capillary waves

    Uchiyama, Y

    Others, Elsevier, Mar. 2019, English

    Dictionary or encycropedia

  • Multiscale routes to supply nutrients through the Kuroshio nutrient stream, In: Kuroshio Current: Physical, Biogeochemical and Ecosystem Dynamics

    Nagai, T, Clayton, S, Uchiyama, Y

    Others, John Wiley & Sons, Mar. 2019, English, Multiscale routes to supply nutrients through the Kuroshio nutrient stream, In: Kuroshio Current: Physical, Biogeochemical and Ecosystem Dynamics, Geophysical Monograph Series, Eds: Nagai, T., Saito, H., Suzuki, K. and Takahashi, M., John Wiley & Sons, NY, ISBN: 1119428343

    Scholarly book

  • Encyclopedia of Ocean Sciences 3rd Edition

    Uchiyama, Y

    Joint editor, Academic Press, Mar. 2019, English, ISBN: 9780128130810

    Dictionary or encycropedia

  • ゼロから学ぶ土木の基本 水理学

    UCHIYAMA YUSUKE

    Single work, オーム社, Jan. 2013, Japanese, ISBN: 9784274213205

    Textbook

Presentations

  • Generation mechanism of tidally-driven submesoscale eddies in an estuary

    Uchiyama, Y

    Kobe University Academic Research and Education Forum on Water and Environment co-organized with The University of Western Australia (online), 04 Nov. 2021, English

    [Invited]

    Nominated symposium

  • Marine environmental assessments in Japan based on a multi-nested 3-D circulation model

    Uchiyama, Y

    The 3rd JSCE-CCES Joint Symposium Online, 21 Oct. 2021, English

    [Invited]

    Invited oral presentation

  • Generation Mechanism of Tidally-driven Whirlpools at a Narrow Strait in an Estuary

    Uchiyama, Y, Zhang, X, Yanase, S

    4th International Symposium on Green and Sustainable Technology (ISGST) 2021 (online), 04 Oct. 2021, English

    Oral presentation

  • マルチクラス3次元懸濁質輸送モデルを用いた福島沿岸域における陸域起源懸濁態放射性核種動態の解析

    内山雄介, 東 晃平, 徳永夏樹

    2021年度日本海洋学会秋季大会(オンライン開催), 15 Sep. 2021, Japanese

    Oral presentation

  • 鳴門海峡でなぜ渦が発生するか

    内山雄介

    渦の魅力フォーラム2021(オンライン開催), 15 May 2021, Japanese

    [Invited]

    Public discourse

  • 最先端の計算科学技術と海洋環境研究

    内山雄介

    EMECS海洋環境科学セミナー2020, 12 Dec. 2020, Japanese

    [Invited]

    Public discourse

  • 海の仕事に就きたい人へ〜学部の選択と卒業後のキャリアパス,

    内山雄介

    EMECS海洋環境科学セミナー2020, 12 Dec. 2020, Japanese

    [Invited]

    Public discourse

  • Nearshore transport of suspended radiocesium in the Fukushima coast derived from Niida River during Typhoon Wipha in fall 2013

    Uchiyama, Y

    Joint special seminar of CRIEPI and IER - A Lagrangian model analysis of spatiotemporal particle behavior for radiocesium and marine food chain transfer, Institute of Environmental Radioactivity, Fukushima University, Fukushima, Japan. (invited), 29 Nov. 2019, English

    [Invited]

    Nominated symposium

  • 海洋モデリング技術を用いた南シナ海の海洋構造物に作年用する外力評価,

    高浦 育, 内山雄介

    2019年度土木学会関西支部次学術講演会講演要旨集,大阪大学 吹田キャンパス, 25 May 2019, Japanese

    Oral presentation

  • 新田川から放出された懸濁態放射性核種の沿岸域での輸送特性について

    徳永夏樹, 内山雄介

    2019年度土木学会関西支部年次学術講演会講演要旨集,大阪大学 吹田キャンパス, 25 May 2019, Japanese

    Oral presentation

  • Evolution of downscaling ocean modeling and its application to the metocean forcing evaluation for offshore structures around Malaysia

    Uchiyama, Y

    Offshore Engineering Lecture Series at Civil and Environmental Engineering Department, Universiti Teknologi Petronas, Bandar Seri Iskandar, Perak, Malaysia, 29 Apr. 2019, English

    [Invited]

    Public discourse

  • Multiple-scale variations of wind-generated wave in the Southern California Bight

    Cao, Y, Dong, C, Uchiyama, Y, Wang, J, Yin, X

    20th Pacific Asian Marginal Seas (PAMS 2019), Mar. 2019, English, Kaohsiung, Taiwan, International conference

    Poster presentation

  • Interisland coral connectivity across the Nansei Archipelago, the East China Sea: Dynamical influences of the Kuroshio

    Uchiyama, Y, Odani, S, Kashima, M, Kamidaira, Y, Mitarai, S

    20th Pacific Asian Marginal Seas (PAMS 2019), Mar. 2019, English, Kaohsiung, Taiwan, International conference

    Oral presentation

  • A medium-term reanalysis of synoptic circulations in the South China Sea using a HYCOM-ROMS downscaling ocean model

    Takaura, N, Uchiyama, Y, Zafarullah, N, Nakayama, A

    20th Pacific Asian Marginal Seas (PAMS 2019), Mar. 2019, English, Kaohsiung, Taiwan, International conference

    Poster presentation

  • A preliminary analysis of a newly-developed regional ocean data assimilation system: A case of Tokyo Bay in summer

    Takatama, K, Kurosawa, K, Uchiyama, Y, Miyoshi, T

    7th International Symposium on Data Assimilation (ISDA2019), Jan. 2019, English, Kobe, Japan, International conference

    Oral presentation

  • Nonlinear internal waves and mixing generated by an interaction of background flows and tides

    Masunaga, E, Uchiyama, Y, Yamazaki, H

    AGU Fall Meeting 2018, Dec. 2018, English, Washington D.C., USA, International conference

    Oral presentation

  • Enhancement of interisland coral connectivity by the Kuroshio across the Nansei Archipelago, the East China Sea

    Uchiyama, Y, Odani, S, Kashima, M, Kamidaira, Y, Mitarai, S

    AGU Fall Meeting 2018, Dec. 2018, English, Washington D.C., USA, International conference

    Oral presentation

  • Can alternative operations at a sewage treatment plant reduce accumulation of the effluent in an adjacent seaweed farm?

    Zhang, X, Uchiyama, Y

    AGU Fall Meeting 2018, Dec. 2018, English, Washington D.C., USA, International conference

    Poster presentation

  • Analysis on 3D structures of oceanic mesoscale eddies in the North Pacific by using a velocity-based eddy detection algorithm

    Okada, N, Uchiyama, Y, Dong, C

    AGU Fall Meeting 2018, Dec. 2018, English, Washington D.C., USA, International conference

    Poster presentation

  • 石西礁湖周辺海域から石西礁湖内部へのサンゴ卵輸送の研究

    Takeda, N, Kashima, M, Odani, S, Uchiyama, Y

    日本サンゴ礁学会第21回大会, Nov. 2018, Japanese, 琉球大学, Domestic conference

    Poster presentation

  • Downscaling ocean modeling and its application to coastal environmental problems

    Uchiyama, Y

    Special Seminar at Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman (UTAR), Nov. 2018, English, Kampar, Perak, Malaysia, International conference

    [Invited]

    Invited oral presentation

  • 和歌山県田辺湾における海水交換特性の季節変化とその形成メカニズムに関する研究

    Okada, N, Uchiyama, Y

    平成30年度瀬戸内海研究フォーラム in 兵庫, Aug. 2018, Japanese, 神戸大学, Domestic conference

    Poster presentation

  • Impacts of wastewater effluent on a seaweed farm in Osaka Bay in different discharge scenarios

    Zhang, X, Uchiyama, Y

    平成30年度瀬戸内海研究フォーラム in 兵庫, Aug. 2018, English, 神戸大学, Domestic conference

    Poster presentation

  • 和歌山県田辺湾の海水交換に及ぼす海洋構造の周期的変動と風の影響について

    Okada, N, Uchiyama, Y

    H30年度複雑熱流体工学研究センター学生発表会, Jul. 2018, Japanese, 神戸大学, Domestic conference

    Poster presentation

  • Numerical assessment of sewage effluent on a seaweed farm in the northeastern Seto Inland Sea, Japan

    Zhang, X, Uchiyama, Y

    H30年度複雑熱流体工学研究センター学生発表会, Jul. 2018, English, 神戸大学, Domestic conference

    Poster presentation

  • Multiple-scale variations of wind-wave in the Southern California Bight

    Cao, Y, Dong, C, Uchiyama, Y, Wang, J, Yin, X

    2nd International Workshop on Regional Ocean Modeling and Observation, Jul. 2018, English, Nanjing University of Information Science and Technology (NUIST), Nanjing, China, C, International conference

    Poster presentation

  • Impacts of wastewater effluent on a seaweed farm in Osaka Bay in different discharge scenarios

    Zhang, X, Uchiyama, Y

    2nd International Workshop on Regional Ocean Modeling and Observation, Jul. 2018, English, Nanjing University of Information Science and Technology (NUIST), Nanjing, China, International conference

    Poster presentation

  • A post-disaster assessment on coastal dispersal of suspended radio-cesium after the Fukushima nuclear accident with a coupled river-ocean-wave-sediment model

    Uchiyama, Y

    2nd International Workshop on Regional Ocean Modeling and Observation, Jul. 2018, English, Nanjing University of Information Science and Technology (NUIST), Nanjing, China, International conference

    [Invited]

    Invited oral presentation

  • 台風出水に伴う新田川起源懸濁態放射性核種の沿岸域でのインベントリ解析

    Uchiyama, Y

    放射性物質環境動態・環境および生物への影響に関する学際共同研究2018年度キックオフ・シンポジウム, Jun. 2018, Japanese, 筑波大学, Domestic conference

    [Invited]

    Nominated symposium

  • Seasonal variability of eddy-induced vertical nutrient flux and associated upper-ocean primary production along the Kuroshio

    Uchiyama, Y, Suzue, Y, Yamazaki, H

    AOGS 15th Annual Meeting (AOGS 2018), Jun. 2018, English, Honolulu, HI, USA, International conference

    Oral presentation

  • Research on the multi-scale spatial and temporal variation of waves in the Southern California Bight

    Cao, Y, Dong, C, Uchiyama, Y, Wang, J, Yin, X

    AOGS 15th Annual Meeting (AOGS 2018), Jun. 2018, English, Honolulu, HI, USA, International conference

    Oral presentation

  • Oceanic Dynamics and Modeling: Implications to marine biological connectivity studies

    Uchiyama, Y

    RinkaiHackathon2018, Jun. 2018, English, Marine Biological Laboratory, Hiroshima University at Mukaishima Island, Japan, International conference

    [Invited]

    Invited oral presentation

  • Multiscale transport, stirring, and mixing processes to supply nutrients through the Kuroshio nutrient stream

    Nagai, T, Clayton, S, Uchiyama, Y

    Japan Geoscience Union Meeting 2018 (JpGU 2018), May 2018, English, Chiba, Japan, International conference

    Oral presentation

  • Highly nonlinear internal waves excited by an interaction of tides and the Kuroshio, Japan

    Masunaga, E, Uchiyama, Y, Yamazaki, H

    Japan Geoscience Union Meeting 2018 (JpGU 2018), May 2018, English, Chiba, Japan, International conference

    Oral presentation

  • Storm-driven flood and associated coastal dispersal of suspended radiocesium from Niida River: A high-resolution numerical assessment with a coupled river-ocean-wave-sediment model

    Uchiyama, Y, Aduma, K, Iwasaki, T, Odani, S, Kamidaira, Y, Tsumune, D, Shimizu, Y, Onda, Y

    European Geosciences Union General Assembly 2018 (EGU2018), Apr. 2018, English, Vienna, Austria, International conference

    Poster presentation

  • On the Interaction of Eddies and Surface Waves in Southern California

    Akan, C, McWilliams, J.C, Uchiyama, Y, Romero, L

    2018 Ocean Sciences Meeting, Feb. 2018, English, Portland, OR, USA, International conference

    Oral presentation

  • 石西礁湖周辺海域から黒潮下流域へのサンゴ卵輸送の研究

    Takeda, N, Kashima, M, Odani, S, Uchiyama, Y

    2017年度日本海洋学会秋季大会, Oct. 2017, Japanese, 仙台市, Domestic conference

    Oral presentation

  • Submesoscale eddy-induced mixing and dispersion of radioactive tracer off the northeastern Pacific coast of Japan

    Kamidaira. Y, Kawamura, H, Kobayashi, T, Uchiyama, Y, Furuno, A

    AOGS 14th Annual Meeting (AOGS 2017), Aug. 2017, English, Singapore, International conference

    Oral presentation

  • Numerical simulations of the interaction between internal waves and the Kuroshio Current over the Izu-Ogasawara Ridge

    Masunaga, E, Auger, G, Rayson, M, Fringer, O, Uchiyama, Y, Yamazaki, H

    AOGS 14th Annual Meeting (AOGS 2017), Aug. 2017, English, Singapore, International conference

    Oral presentation

  • Inter-annual and seasonal variability of upper-ocean primary production along the Kuroshio off Japan

    Zhang, X, Uchiyama, Y

    AOGS 14th Annual Meeting (AOGS 2017), Aug. 2017, English, Singapore, International conference

    Oral presentation

  • Impact of the Kuroshio on dispersal of coral spawn and larvae around Ryukyu Islands in the East China Sea

    Odani, S, Uchiyama, Y, Kashima, M, Kamidaira, Y, Mitarai, S

    AOGS 14th Annual Meeting (AOGS 2017), Aug. 2017, English, Singapore, International conference

    Oral presentation

  • Eddy analysis in the North Pacific based on altimetry-derived surface currents

    Okada, N, Uchiyama, Y, Liu, Y, Dong, C

    AOGS 14th Annual Meeting (AOGS 2017), Aug. 2017, English, Singapore, International conference

    Oral presentation

  • A high-resolution coastal forecasting system with a 3DVAR assimilation optimal for a semi-enclosed estuary

    Kurosawa, K, Uchiyama, Y, Miyoshi, T

    AOGS 14th Annual Meeting (AOGS 2017), Aug. 2017, English, Singapore, International conference

    Oral presentation

  • 海洋表層地衡流を用いた eddy tracking による北太平洋における中規模渦の発生伝播特性の解析

    Okada, N, Uchiyama, Y

    平成29年度土木学会関西支部年次学術講演会, May 2017, Japanese, 大阪工業大学,大阪市, Domestic conference

    Oral presentation

  • Numerical simulations of internal wave dynamics in the vicinity of Izu-Oshima Island, off Sagami Bay, Japan

    Masunaga, E, Suzue, Y, Uchiyama, Y, Yamazaki, H

    JpGU-AGU Joint Meeting 2017, May 2017, English, Chiba, Japan, International conference

    Oral presentation

  • On generation and propagation of oceanic mesoscale eddies in the North Pacific analyzed with an eddy-tracking algorithm

    Okada, N, Uchiyama, Y, Liu, Y, Dong. C

    19th Pacific-Asian Marginal Seas Meeting (PAMS 2017), Apr. 2017, English, Jeju, South Korea, International conference

    Poster presentation

  • Model assessment of wastewater effluent on a seaweed farm in Osaka Bay, Japan

    Zhang, X, Uchiyama, Y, Suzue, Y

    19th Pacific-Asian Marginal Seas Meeting (PAMS 2017), Apr. 2017, English, Jeju, South Korea, International conference

    Poster presentation

  • Meridional transition of upper-ocean primary productivity due to diapycnal eddy mixing across the Kuroshio off Japan

    Uchiyama, Y, Suzue, Y, Yamazaki, H

    19th Pacific-Asian Marginal Seas Meeting (PAMS 2017), Apr. 2017, English, Jeju, South Korea, International conference

    Oral presentation

  • Intrinsic low-frequency variability in transient three-dimensional rip currents

    Uchiyama, Y, McWilliams, J.C, Akan, C

    19th Pacific-Asian Marginal Seas Meeting (PAMS 2017), Apr. 2017, English, Jeju, South Korea, International conference

    Poster presentation

  • Drop size distribution under severe wind condition in marine observation and wind-tunnel experiment

    Okachi, H, Yamada, T.J, Watanabe, Y, Saruwatari, A, Ohtsuka, J, Mori, N, Baba, Y, Mizutani, H, Kubo, T, Ninomiya, J, Uchiyama, Y

    European Geosciences Union General Assembly 2017 (EGU2017), Apr. 2017, English, Vienna, Austria, International conference

    Oral presentation

  • Development of a coastal forecasting system with a 3DVAR assimilation for the Seto Inland Sea, Japan

    Kurosawa, K, Uchiyama, Y, Miyoshi, T

    19th Pacific-Asian Marginal Seas Meeting (PAMS 2017), Apr. 2017, English, Jeju, South Korea, International conference

    Poster presentation

  • 福島原発由来の放射性核種の環境動態に関する学際的研究(3)海洋における放射性物質の分布状況・要因の把握

    Yamada, M, Aoyama, M, Ikehara, K, Inomata, Y, Uematsu, M, Uchiyama, Y, Kaeriyama, H, Kato, Y, Kusakabe, M, Kumamoto, Y, Takahata, N, Tazoe, H, Zhang, K, Tsubono, T, Tsumune, D, Tsung. T, Nagai, S, Hamajima, Y, Honda, M, Misumi, K, Yang, K

    第18回環境放射能研究会, Mar. 2017, Japanese, 筑波大学,茨城県筑波市, Domestic conference

    Oral presentation

  • Evolution of high-resolution regional ocean modeling: applications to waste water and larval dispersal in an estuary

    Uchiyama, Y

    2nd International Symposium on Green and Sustainable Technology (ISGST2017), Jan. 2017, English, Kampar, Malaysia, International conference

    Keynote oral presentation

  • Quantifying coastal connectivity of coral spawn and larvae around Ryukyu Islands in the East China Sea

    Odani, S, Uchiyama, Y, Yamanishi, T, Kamidaira, Y, Mitarai, S

    AGU Fall Meeting 2016, Dec. 2016, English, San Francisco, CA, USA, International conference

    Poster presentation

  • Modeling nearshore dispersal of river-derived multi-class suspended sediments and radionuclides during a flood event around the mouth of Niida River, Fukushima, Japan

    Uchiyama, Y, Yamanishi, T, Iwasaki, T, Shimizu, Y, Tsumune, D, Misumi, K, Onda, Y

    AGU Fall Meeting 2016, Dec. 2016, English, San Francisco, CA, USA, International conference

    Oral presentation

  • Impact of a diversion of sewage effluent on a seaweed farm in the Seto Inland Sea, Japan

    Zhang, X, Uchiyama, Y, Suzue, Y

    AGU Fall Meeting 2016, Dec. 2016, English, San Francisco, CA, USA, International conference

    Poster presentation

  • Development of a three-dimensional variational data assimilation system for the Seto Island Sea, Japan

    Kurosawa, K, Uchiyama, Y

    AGU Fall Meeting 2016, Dec. 2016, English, San Francisco, CA, USA, International conference

    Poster presentation

  • Subtidal and semi-duirnal intrusion of offshore water into Tanabe Bay predicated upon a comprehensive field observation and a high-resolution down-scaling ocean modeling

    Uchiyama, Y

    International workshop on field measurements in fluvial and coastal areas and the utilization of the observed data, Nov. 2016, English, Wakayama, Japan, International conference

    Keynote oral presentation

  • 台風通過に伴う黒潮流路変動および紀伊水道への暖水波及について

    Tada, H, Uchiyama, Y

    2016年度日本海洋学会秋季大会, Sep. 2016, Japanese, 鹿児島大学,鹿児島市, Domestic conference

    Oral presentation

  • 船舶搭載用コンパクト海洋モデルの構築とウェザールーティングへの応用

    Kurosawa, K, Uchiyama, Y, Kosako, T, Tada, H

    2016年度日本海洋学会秋季大会, Sep. 2016, Japanese, 鹿児島大学,鹿児島市, Domestic conference

    Oral presentation

  • 沖縄本島周辺海域におけるメソスケール渦の消長とそれに伴う黒潮反流の季節変動について

    Odani, S, Uchiyama, Y, Yamanishi, T, Mitarai, S

    2016年度日本海洋学会秋季大会, Sep. 2016, Japanese, 鹿児島大学,鹿児島市, Domestic conference

    Oral presentation

  • ROMS-NPZDモデルを用いた黒潮域における 一次生産に対するメソスケール海洋変動の影響評価

    Suzue, Y, Uchiyama, Y, Yamazaki, H

    2016年度日本海洋学会秋季大会, Sep. 2016, Japanese, 鹿児島大学,鹿児島市, Domestic conference

    Oral presentation

  • Utilizing a regional ocean model for weather routing for optimal vessel navigation

    Kurosawa, K, Uchiyama, Y, Kosako, T, Tada, H

    AOGS 13th Annual Meeting (AOGS 2016), Aug. 2016, English, Beijing, China, International conference

    Oral presentation

  • Upper ocean dynamics and associated water exchange at the entrance of a semi-enclosed bay based on an in-situ ADCP measurement

    Uchiyama, Y, Yoshiki, T, Tada, H, Baba, Y, Mizutani, H, Kubo, T, Mori, N, Saruwatari, A, Otsuka, J, Ninomiya, J, Watanabe, Y, Yamada, T

    AOGS 13th Annual Meeting (AOGS 2016), Aug. 2016, English, Beijing, China, International conference

    Oral presentation

  • Surface mixing and dispersion of radioactive tracer due to submesoscale eddies off the northeastern Pacific coast of Japan

    Kamidaira, Y, Kawamura, H, Kobayashi, T, Uchiyama, Y

    AOGS 13th Annual Meeting (AOGS 2016), Aug. 2016, English, Beijing, China, International conference

    Oral presentation

  • Seasonal and inter-annual variability of larval dispersal and ambient currents in the Seto Inland Sea, Japan

    Kosako, T, Uchiyama, Y, Mitarai, S

    AOGS 13th Annual Meeting (AOGS 2016), Aug. 2016, English, Beijing, China, International conference

    Oral presentation

  • Modeling coastal dispersal of wastewater effluent from multiple sources in the Seto Inland Sea

    Zhang, X, Uchiyama, Y, Suzue, Y

    AOGS 13th Annual Meeting (AOGS 2016), Aug. 2016, English, Beijing, China, International conference

    Oral presentation

  • Influences of meso- and submeso-scale oceanic variability on the primary production in the Kuroshio region off Japan

    Suzue, Y, Uchiyama, Y, Yamazaki, H

    AOGS 13th Annual Meeting (AOGS 2016), Aug. 2016, English, Beijing, China, International conference

    Oral presentation

  • Impacts of typhoons on upper-ocean mixing and the Kuroshio in the northwestern Pacific Ocean

    Tada, H, Uchiyama, Y

    AOGS 13th Annual Meeting (AOGS 2016), Aug. 2016, English, Beijing, China, International conference

    Oral presentation

  • Asymmetric oceanic responses around Okinawa Island in the East China Sea

    Odani, S, Uchiyama, Y, Yamanishi, T, Kamidaira, Y, Mitarai, S

    AOGS 13th Annual Meeting (AOGS 2016), Aug. 2016, English, Beijing, China, International conference

    Oral presentation

  • 細密気象・海象情報とグラフ理論を統合した最適航路評価法の開発

    Kurosawa, K, Uchiyama, Y

    平成28年度土木学会関西支部年次学術講演会, Jun. 2016, Japanese, 立命館大学,滋賀県草津市, Domestic conference

    Oral presentation

  • 沖縄本島周辺海域におけるリッジ地形による海洋構造の非対称性に関する研究

    Odani, S, Uchiyama, Y

    平成28年度土木学会関西支部年次学術講演会, Jun. 2016, Japanese, 立命館大学,滋賀県草津市, Domestic conference

    Oral presentation

  • ADCP観測に基づく半閉鎖性海域湾口部における海表面境界層内の力学特性に関する研究

    Yoshiki, T, Uchiyama, Y

    平成28年度土木学会関西支部年次学術講演会, Jun. 2016, Japanese, 立命館大学,滋賀県草津市, Domestic conference

    Oral presentation

  • 細密気象・海象情報とグラフ理論を統合した最適航路評価法の開発

    Kurosawa, K, Uchiyama, Y, Kosako, T, Tada, H

    日本航海学会H28年度春季大会, May 2016, Japanese, 神戸市, Domestic conference

    Oral presentation

  • Wave-current interaction in coastal and shelf seas

    Uchiyama, Y

    International Workshop on Regional Oceanic Modelling and Observation, May 2016, English, Nanjing, China, International conference

    [Invited]

    Invited oral presentation

  • Impact of mesoscale recirculation of the Kuroshio on asymmetric oceanic structure around Okinawa Island in the East China Sea

    Odani, S, Uchiyama, Y, Yamanishi, T, Kamidaira, Y, Mitarai, S

    Japan Geosciences Union Meeting 2016 (JpGU 2016), May 2016, English, Chiba, Japan, International conference

    Poster presentation

  • Forcing mechanism controlling the variability of circulations and associated larval transport in the Seto Inland Sea, Japan

    Uchiyama, Y, Kosako, T, Mitarai, S

    Japan Geosciences Union Meeting 2016 (JpGU 2016), May 2016, English, Chiba, Japan, International conference

    Oral presentation

  • Coastal ocean processes responsible for radionuclide dispersion: A case study for Seto Inland Sea and Enshu-nada

    Masumoto, Y, Tsumune, D, Guo, X, Uchiyama, Y, Miyazawa, Y

    Japan Geosciences Union Meeting 2016 (JpGU 2016), May 2016, English, Chiba, Japan, International conference

    Oral presentation

  • Three-dimensional modeling of oceanic dispersal of land-derived multi-class suspended radionuclides after the Fukushima Dai-ichi accident

    Uchiyama, Y, Yamanishi, T, Tsumune, D, Misumi, K, Onda, Y

    European Geosciences Union General Assembly 2016 (EGU2016), Apr. 2016, English, Vienna, Austria, International conference

    Poster presentation

  • 幼稚仔分散評価のための粒子追跡モデルの感度解析

    Kosako, T, Uchiyama, Y, Mitarai, S

    2016年度日本海洋学会春季大会・講演要旨集, Mar. 2016, Japanese, 東京大学本郷キャンパス,東京, Domestic conference

    Oral presentation

  • 福島新田川周辺海域における出水イベントに伴う懸濁態放射性核種の分散解析

    Yamanishi, T, Uchiyama, Y, Iwasaki, T, Shimizu, Y, Tsumune, D, Misumi, K, Onda, Y

    2016年度日本海洋学会春季大会・講演要旨集, Mar. 2016, Japanese, 東京大学本郷キャンパス,東京, Domestic conference

    Oral presentation

  • マルチクラス懸濁質輸送モデルによる福島沿岸域堆積物シミュレーション

    Uchiyama, Y

    2016年度沿岸海洋シンポジウム:震災復興に対する沿岸海洋学の貢献, Mar. 2016, Japanese, 東京大学本郷キャンパス,東京, Domestic conference

    [Invited]

    Invited oral presentation

  • Topographic effects on low-frequency variability in three-dimensional transient littoral currents

    Uchiyama, Y, McWilliams, J.C, Akan, C

    Ocean Sciences Meeting 2016, Feb. 2016, English, New Orleans, LA, USA, International conference

    Poster presentation

  • Near-inertial resonance, upper-ocean stirring and impacts on the Kuroshio path due to typhoons in the northwestern Pacific Ocean

    Tada, H, Uchiyama, Y

    Ocean Sciences Meeting 2016, Feb. 2016, English, New Orleans, LA, USA, International conference

    Poster presentation

  • Characterizing Stormwater Dispersion and Dilution from Small Coastal Streams

    Romero, L, Siegel, D.A, McWilliams, J.C, Uchiyama, Y, Jones, C

    Ocean Sciences Meeting 2016, Feb. 2016, English, New Orleans, LA, USA, International conference

    Oral presentation

  • Biogeochamical responses to meso- and submesoscale oceanic variability in the Kuroshio region

    Suzue, Y, Uchiyama, Y, Yamazaki, H

    Ocean Sciences Meeting 2016, Feb. 2016, English, New Orleans, LA, USA, International conference

    Poster presentation

  • 津波・高潮による沿岸災害〜発生・伝播・増幅メカニズムと防災対策

    Uchiyama, Y

    第9回災害対策セミナー in Kobe,シンポジウム「神戸における自然災害の防止・減災を目指して」, Jan. 2016, Japanese, 神戸国際会議場, Domestic conference

    [Invited]

    Invited oral presentation

  • Three-dimensional modeling of time-dependent wave-driven currents on a sandy beach

    Uchiyama, Y

    Seminar on Simulation of Coastal Processes, Nov. 2015, English, Kusatsu, Shiga, Japan, International conference

    [Invited]

    Invited oral presentation

  • Near-inertial resonance and upper-ocean stirring due to typhoons in the northwestern Pacific margin

    Tada, H, Uchiyama, Y

    The 2nd Open Science Symposium on Western Pacific Ocean Circulation and Climate (2nd OSS-2015), Oct. 2015, English, Busan, South Korea, International conference

    Oral presentation

  • Influences of submesoscale eddies on synoptic and mesoscale dynamics in the Japan Sea

    Uchiyama, Y, Miyazaki, D, Kanki, R

    The 2nd Open Science Symposium on Western Pacific Ocean Circulation and Climate (2nd OSS-2015), Oct. 2015, English, Busan, South Korea, International conference

    Oral presentation

  • 福島沿岸域における浅海域・河川由来懸濁態放射性核種の海洋分散

    Yamanishi, T, Uchiyama, Y, Tsumune, D, Misumi, K

    2015年度日本海洋学会秋季大会・講演要旨集, Sep. 2015, Japanese, 愛媛大学,愛媛県松山市, Domestic conference

    Oral presentation

  • 太平洋北西海域および黒潮域における台風通過に伴う海洋構造変化について

    Tada, H, Uchiyama, Y

    2015年度日本海洋学会秋季大会・講演要旨集, Sep. 2015, Japanese, 愛媛大学,愛媛県松山市, Domestic conference

    Oral presentation

  • 黒潮離接岸に伴う瀬戸内海内部における幼稚仔分散の変動特性

    Kosako, T, Uchiyama, Y, Mitarai, S

    2015年度日本海洋学会秋季大会・講演要旨集, Sep. 2015, Japanese, 愛媛大学,愛媛県松山市, Domestic conference

    Oral presentation

  • 伊予灘および遠州灘沿岸域における陸域起源物質海洋分散の季節変動特性

    Suzue, Y, Uchiyama, Y

    2015年度日本海洋学会秋季大会・講演要旨集, Sep. 2015, Japanese, 愛媛大学,愛媛県松山市, Domestic conference

    Oral presentation

  • Submesoscale stirring of the Kuroshio in the East China Sea

    Uchiyama, Y

    International symposium on Submesoscale Oceanography : Prospect for a new world, JOS Fall Meeting 2015, Sep. 2015, English, Matsuyama, Japan, International conference

    [Invited]

    Invited oral presentation

  • Modeling oceanic responses to typhoons in the northwestern Pacific margin

    Uchiyama, Y, Tada, H

    AOGS 12th Annual Meeting (AOGS 2015), Aug. 2015, English, Singapore, International conference

    Oral presentation

  • Anisotropic Relative Dispersion near the Southern California Coast

    Romero, L, Uchiyama, Y, Ohlmann, C, McWilliams, J.C, Siegel, D.A

    Lagrangian Analysis and Prediction of Coastal and Ocean Dynamics (LAPCOD2015), Jul. 2015, English, Winter Harbor, MA, USA, International conference

    Oral presentation

  • 北太平洋西岸海域における台風通過に伴う海洋構造変化に関する研究

    Tada, H, Uchiyama, Y

    平成27年度土木学会関西支部年次学術講演会・講演概要集, May 2015, Japanese, 摂南大学,大阪府寝屋川市, Domestic conference

    Oral presentation

  • 原子力発電所からの放射性物質の漏洩を想定した海洋拡散シミュレーション手法の構築 (3) -瀬戸内海,関東・東海,東北沿岸モデルの比較-

    Uchiyama, Y

    海洋放射能汚染緊急対応予測モデルに関するワークショップ, May 2015, Japanese, 福島大学,福島県福島市, Domestic conference

    [Invited]

    Nominated symposium

  • Offline passive tracerモデルの開発と瀬戸内海西部海域への適用

    Suzue, Y, Uchiyama, Y

    平成27年度土木学会関西支部年次学術講演会・講演概要集, May 2015, Japanese, 摂南大学,大阪府寝屋川市, Domestic conference

    Oral presentation

  • Modeling dispersal of land-derived suspended radionuclides in the Fukushima coast

    Yamanishi, T, Uchiyama, Y, Onda, Y, Tsumune, D, Misumi, K

    Japan Geoscience Union Meeting 2015 (JpGU2015), May 2015, English, Chiba, Japan, International conference

    Oral presentation

  • Coastal dispersal of the land-derived tracer in an estuary and a continental shelf margin

    Uchiyama, Y, Suzue, Y

    Japan Geoscience Union Meeting 2015 (JpGU2015), May 2015, English, Chiba, Japan, International conference

    [Invited]

    Invited oral presentation

  • Topographic effects on submesoscale eddy mixing around the Kuroshio off the Ryukyu Islands

    Uchiyama, Y, Kamidaira, Y

    18th Pacific-Asian Marginal Seas Meeting (PAMS 2015), Apr. 2015, English, Naha, Japan, International conference

    Oral presentation

  • Oceanic and coastal responses to super typhoons in the northwestern Pacific marginal seas

    Tada, H, Uchiyama, Y

    18th Pacific-Asian Marginal Seas Meeting (PAMS 2015), Apr. 2015, English, Naha, Japan, International conference

    Oral presentation

  • Effects of fluctuating Kuroshio path on larval dispersal in the Seto Inland Sea

    Kosako, T, Uchiyama, Y, Mitarai, S

    18th Pacific-Asian Marginal Seas Meeting (PAMS 2015), Apr. 2015, English, Naha, Japan, International conference

    Poster presentation

  • Coastal dispersal of Eulerian passive tracer: Comparative experiments in an estuary and a continental shelf margin

    Suzue, Y, Uchiyama, Y

    18th Pacific-Asian Marginal Seas Meeting (PAMS 2015), Apr. 2015, English, Naha, Japan, International conference

    Poster presentation

  • 波−流れ相互作用〜海浜流・漂砂・沿岸流動解析への応用

    Uchiyama, Y

    港湾空港技術研究所平成26年度海岸工学特別講演会, Jan. 2015, Japanese, 独立行政法人港湾空港技術研究所, 横須賀, Domestic conference

    [Invited]

    Invited oral presentation

  • Wave-current interaction in evolution of rip channel system

    Uchiyama, Y, Miyazaki, D, Kaida, H

    AGU Fall Meeting 2014, Dec. 2014, English, San Francisco, CA, USA, International conference

    Oral presentation

  • Potential utility of three-dimensional temperature and salinity fields estimated from satellite altimetry and Argo data for improving mesoscale reproducibility in regional ocean modeling

    Kanki, R, Uchiyama, Y, Miyazaki, D, Takano, A, Miyazawa, Y, Yamazaki, H

    AGU Fall Meeting 2014, Dec. 2014, English, San Francisco, CA, USA, International conference

    Oral presentation

  • Modeling larval dispersal and quantifying coastal connectivity based on a downscaling ocean model in Seto Inland Sea, Japan

    Kosako, T, Uchiyama, Y, Mitarai, S

    AGU Fall Meeting 2014, Dec. 2014, English, San Francisco, CA, USA, International conference

    Poster presentation

  • Impact of submesoscale eddies on synoptic and mesoscale oceanic structures in a continental shelf margin analyzed with a downscaling ocean model of Japan Sea

    Miyazaki, D, Uchiyama, Y, Kanki, R, Miyazawa, Y

    AGU Fall Meeting 2014, Dec. 2014, English, San Francisco, CA, USA, International conference

    Poster presentation

  • Enhancement of eddy heat transport due to the anticyclonic submesoscale eddies around Ryukyu Islands near Kuroshio in East China Sea

    Kamidaira, Y, Uchiyama, Y, Mitarai, S, Miyazawa, Y

    AGU Fall Meeting 2014, Dec. 2014, English, San Francisco, CA, USA, International conference

    Poster presentation

  • A regional sediment transport modeling for assessing dispersal and recirculation of land-derived radionuclides in the Fukushima coast

    Yamanishi, T, Uchiyama, Y, Tsumune, D, Miyazawa, Y

    AGU Fall Meeting 2014, Dec. 2014, English, San Francisco, CA, USA, International conference

    Poster presentation

  • 陸棚循環流に対する波-流れ相互作用の効果について

    Uchiyama, Y, Kaida, H

    日本流体力学会年会2014講演論文集, Sep. 2014, Japanese, Domestic conference

    Oral presentation

  • 陸域起源放射性核種の海域移行定量化を目的とした領域土砂輸送モデルの開発

    Yamanishi, T, Uchiyama, Y, Tsumune, D, Miyazawa, Y

    第22回地球環境シンポジウム講演集, Sep. 2014, Japanese, 土木学会, Domestic conference

    Poster presentation

  • 日本海全域を対象とした高解像度ROMSモデルによる海況評価

    Miyazaki, D, Uchiyama, Y, Kanki, R, Miyazawa, Y

    2014年度日本海洋学会秋季大会・講演要旨集, Sep. 2014, Japanese, Nagasaki University, Nagasaki, Japan, Domestic conference

    Oral presentation

  • 東シナ海におけるサブメソスケール乱流混合による黒潮暖流の輸送効果の解析

    Kamidaira, Y, Uchiyama, Y

    2014年度日本海洋学会秋季大会・講演要旨集, Sep. 2014, Japanese, Nagasaki University, Nagasaki, Japan, Domestic conference

    Oral presentation

  • 渦解像ダウンスケール海洋モデリングにおけるデータ同化によるメソスケール海洋構造の再現精度について

    Kanki, R, Uchiyama, Y, Miyazaki, D, Takano, A, Miyazawa, Y, Yamazaki, H

    2014年度日本海洋学会秋季大会・講演要旨集, Sep. 2014, Japanese, Nagasaki University, Nagasaki, Japan, Domestic conference

    Oral presentation

  • コネクティビティを用いた瀬戸内海全域における海洋生態系ネットワーク構造の定量的評価

    Kosako, T, Uchiyama, Y, Mitarai, S

    2014年度日本海洋学会秋季大会・講演要旨集, Sep. 2014, Japanese, Nagasaki University, Nagasaki, Japan, Domestic conference

    Oral presentation

  • Regional circulation and dispersal in Seto Inland Sea with offshore influences: Towards an effective estuarine environmental protection strategy

    Uchiyama, Y

    クリタ水・環境科学研究優秀賞受賞講演会, Sep. 2014, English, Tokyo, Japan, Domestic conference

    [Invited]

    Invited oral presentation

  • Inner Shelf Dispersion and Dilution of Creek Runoff

    Romero, L, Uchiyama, Y, Siegel, D.A, McWilliams, J

    61st Annual Eastern Pacific Ocean Conference (EPOC 2014), Sep. 2014, English, Mt. Hood, OR, USA, International conference

    Oral presentation

  • Topographic effects of Ryukyu Islands on the enhancement of submesoscale anticyclonic eddies on the eastern side of Kuroshio in East China Sea

    Kamidaira, Y, Uchiyama, Y, Mitarai, S, Miyazawa, Y

    AOGS 11th Annual Meeting (AOGS 2014), Jul. 2014, English, Sapporo, Japan, International conference

    Oral presentation

  • Stochastic analysis with coastal connectivity on larval networks in the Seto Inland Sea

    Kosako, T, Uchiyama, Y, Mitarai, S, Nishii, T

    AOGS 11th Annual Meeting (AOGS 2014), Jul. 2014, English, Sapporo, Japan, International conference

    Poster presentation

  • Experimental development of ocean prediction system for accidental radionuclide dispersion

    Masumoto, Y, Guo, X, Hirose, N, Ikeda, M, Mitsudera, H, Miyazawa, Y, Tsumune, D, Uchiyama, Y

    AOGS 11th Annual Meeting (AOGS 2014), Jul. 2014, English, Sapporo, Japan, International conference

    Poster presentation

  • Effects of wave-current interaction on the inner-shelf eddying flows

    Kaida, H, Uchiyama, Y, McWilliams, J

    AOGS 11th Annual Meeting (AOGS 2014), Jul. 2014, English, Sapporo, Japan, International conference

    Oral presentation

  • Development of a regional sediment transport model for dispersal of land-derived radionuclides in the ocean

    Yamanishi, T, Uchiyama, Y, Tsumune, D, Miyazawa, Y

    AOGS 11th Annual Meeting (AOGS 2014), Jul. 2014, English, Sapporo, Japan, International conference

    Oral presentation

  • Cold water formation in response to typhoon passages in and around Seto Inland Sea, Japan

    Uchiyama, Y, Nishii, T

    AOGS 11th Annual Meeting (AOGS 2014), Jul. 2014, English, Sapporo, Japan, International conference

    Oral presentation

  • A retrospective high-resolution numerical experiment of Japan Sea with a JCOPE2-ROMS downscaling system

    Miyazaki, D, Uchiyama, Y, Kanki, R, Miyazawa, Y

    AOGS 11th Annual Meeting (AOGS 2014), Jul. 2014, English, Sapporo, Japan, International conference

    Oral presentation

  • A sediment transport model for analyzing the environmental dynamics of radionuclides in estuarine and coastal oceans

    Uchiyama, Y, Yamanishi, T, Tsumune, D, Miyazawa, Y

    Japan Geoscience Union Meeting 2014 (JpGU2014), May 2014, Japanese, Yokohama, Japan, International conference

    Oral presentation

  • 太平洋全域における海表面二酸化炭素フラックスと海洋酸性化について

    Matsuyama, M, Kamidaira, Y, Uchiyama, Y

    平成26年度土木学会関西支部年次学術講演会・講演概要集, May 2014, Japanese, 土木学会関西支部, Domestic conference

    Oral presentation

  • 瀬戸内海全域を対象としたコネクティビティによる海洋生態系ネットワーク構造の解析

    Kosako, T, Uchiyama, Y

    平成26年度土木学会関西支部年次学術講演会・講演概要集, May 2014, Japanese, 土木学会関西支部, Domestic conference

    Oral presentation

  • 外洋影響を考慮した紀伊半島田辺湾周辺海域の海洋構造に関する研究

    Matsukawa, D, Uchiyama, Y

    平成26年度土木学会関西支部年次学術講演会・講演概要集, May 2014, Japanese, 土木学会関西支部, Domestic conference

    Oral presentation

  • Heat budget analysis on cooling events associated with typhoon passages in Seto Inland Sea, Japan

    Uchiyama, Y, Nishii, T

    Japan Geoscience Union Meeting 2014 (JpGU2014), May 2014, English, Yokohama, Japan, International conference

    Oral presentation

  • 琉球諸島周辺海域におけるサブメソスケール乱流混合による 黒潮系水塊の波及促進効果の解析

    Kamidaira, Y, Uchiyama, Y, Mitarai, S, Miyazawa, Y, Sakagami, T

    2014年度日本海洋学会春季大会・講演要旨集, Mar. 2014, Japanese, 東京海洋大学品川キャンパス, Domestic conference

    Oral presentation

  • 陸棚から砕波帯までを考慮した沿岸流動モデル

    Uchiyama, Y

    2014年度春季沿岸海洋研究シンポジウム−沿岸高解像モデルの現在と未来 (1) 沿岸海洋物理現象の再現に向けて-, Mar. 2014, Japanese, 東京海洋大学品川キャンパス, Domestic conference

    [Invited]

    Invited oral presentation

  • 放射性核種の海域移行定量化に向けた沿岸土砂輸送モデルの開発

    Yamanishi, T, Uchiyama, Y, Tsumune, D, Miyazawa, Y

    2014年度日本海洋学会春季大会・講演要旨集, Mar. 2014, Japanese, 東京海洋大学品川キャンパス, Domestic conference

    Oral presentation

  • 波−流れ相互作用がサブメソスケール渦の発達に及ぼす影響について

    Kaida, H, Uchiyama, Y, McWilliams, J

    2014年度日本海洋学会春季大会・講演要旨集, Mar. 2014, Japanese, 東京海洋大学品川キャンパス, Domestic conference

    Oral presentation

  • JCOPE2-ROMS ダウンスケーリングシステムによる日本海全域の海況評価

    Miyazaki, D, Uchiyama, Y, Kanki, R, Miyazawa, Y

    2014年度日本海洋学会春季大会・講演要旨集, Mar. 2014, Japanese, Domestic conference

    Oral presentation

  • Wave-current interaction in the surfzone-inner shelf circulations

    Kaida, H, Uchiyama, Y, McWilliams, J

    Ocean Sciences Meeting 2014, Feb. 2014, English, Honolulu, HI, USA, International conference

    Poster presentation

  • Nearshore anisotropic relative dispersion in Southern California

    Romero, L, Uchiyama, Y, Ohlmann, J.C, McWilliams, J.C, Siegel, D.A

    Ocean Sciences Meeting 2014, Feb. 2014, English, Honolulu, HI, USA, International conference

    Poster presentation

  • Model-Data Comparison of Surfzone and Inner-Shelf Circulation during HB06

    Kumar, N, Feddersen, F, Uchiyama, Y, McWilliams, J.C, O'Reilly, W

    Ocean Sciences Meeting 2014, Feb. 2014, English, Honolulu, HI, USA, International conference

    Oral presentation

  • Cooling the upper ocean around Seto Inland Sea due to typhoons

    Nishii, T, Uchiyama, Y, Mori, N, Baba, Y

    Ocean Sciences Meeting 2014, Feb. 2014, English, Honolulu, HI, USA, International conference

    Poster presentation

  • 福島第一原発からの放射性核種の沿岸海洋拡散再解析

    Uchiyama, Y

    Model & Simulation研究会, Dec. 2013, Japanese, 東北大学青葉記念会館, Domestic conference

    [Invited]

    Invited oral presentation

  • 福島第一原発を放出源とする放射性核種の初期分散特性

    Yamanishi, T, Uchiyama, Y, Tsumune, D, Miyazawa, Y

    2013年度日本海洋学会秋季大会・講演要旨集, Sep. 2013, Japanese, Hokkaido University, Sapporo, Japan, Domestic conference

    Oral presentation

  • 波-流れ相互作用による離岸流の抑制効果が海浜地形変化に及ぼす影響

    Miyazaki, D, Uchiyama, Y, Kaida, H

    日本流体力学会年会2013講演論文集, Sep. 2013, Japanese, Domestic conference

    Oral presentation

  • 波−流れ相互作用を考慮した砕波帯−陸棚間の混合過程に関する数値解析

    Kaida, H, Uchiyama, Y, McWilliams, J

    2013年度日本海洋学会秋季大会・講演要旨集, Sep. 2013, Japanese, Hokkaido University, Sapporo, Japan, Domestic conference

    Oral presentation

  • 東シナ海におけるサブメソスケール乱流混合による黒潮系水塊の波及促進効果について

    Kamidaira, Y, Uchiyama, Y, Mitarai, S, Sakagami, T

    日本流体力学会年会2013講演論文集, Sep. 2013, Japanese, Domestic conference

    Oral presentation

  • 大阪湾における3段階ネスティングによる高解像度モデルを用いた下水処理水分散シミュレーション

    Kanki, R, Uchiyama, Y, Nakayama, A

    日本流体力学会年会2013講演論文集, Sep. 2013, Japanese, Domestic conference

    Oral presentation

  • 紀伊半島沿岸域における台風通過に伴う海水温低下機構

    Nishii, T, Uchiyama, Y, Mori, N, Baba, Y

    2013年度日本海洋学会秋季大会・講演要旨集, Sep. 2013, Japanese, Hokkaido University, Sapporo, Japan, Domestic conference

    Oral presentation

  • Wave-current interaction in morphological change on a barred beach

    Miyazaki, D, Uchiyama, Y, Kaida, H

    32nd Int'l Conf. on Simulation Technology (JSST2013), Sep. 2013, English, Tokyo, Japan, International conference

    Oral presentation

  • Wastewater dispersal in Osaka Bay and Harima Nada using a multi-nested high-resolution ocean modeling

    Kanki, R, Uchiyama, Y, Nakayama, A

    32nd Int'l Conf. on Simulation Technology (JSST2013), Sep. 2013, English, Tokyo, Japan, International conference

    Oral presentation

  • Surfzone-inner shelf interaction analyzed with a quintuple nested high resolution ocean model

    Kaida, H, Uchiyama, Y

    32nd Int'l Conf. on Simulation Technology (JSST2013), Sep. 2013, English, Tokyo, Japan, International conference

    Oral presentation

  • Principal component analysis on horizontal acoustic Doppler current profilers measurement

    Phan, T.N.M, Wells, J.C, Uchiyama, Y, Bonner, J.S, Islam, M.S, Kirkey, W.D

    Oceans 2013 MTS/IEEE, Sep. 2013, English, San Diego, CA, USA, International conference

    Oral presentation

  • A numerical study of effects of submesoscale anticyclonic eddies induced by Kuroshio around Ryukyu Islands

    Kamidaira, Y, Uchiyama, Y, Mitarai, S, Sakagami, T

    32nd Int'l Conf. on Simulation Technology (JSST2013), Sep. 2013, English, Tokyo, Japan, International conference

    Oral presentation

  • 3次元海浜流が砕波帯-陸棚間の物質交換に及ぼす影響について

    Kaida, H, Uchiyama, Y, McWilliams, J

    日本流体力学会年会2013講演論文集, Sep. 2013, Japanese, Domestic conference

    Oral presentation

  • Wave-current interaction in inner shelf circulation: a high resolution regional ocean modeling with a vortex-force formalism

    Uchiyama, Y

    International Workshop on Ocean Waves and Related Processes, Jul. 2013, English, Yokohama, Japan, International conference

    [Invited]

    Invited oral presentation

  • 神戸垂水沖を点源とする大阪湾・播磨灘における処理水分散に関する高解像度海洋シミュレーション

    Kanki, R, Uchiyama, Y

    土木学会関西支部年次学術講演会・講演概要集, May 2013, Japanese, Domestic conference

    Oral presentation

  • リップチャンネルの形成に及ぼす流れから波へのフィードバック機構の影響について

    Miyazaki, D, Uchiyama, Y

    土木学会関西支部年次学術講演会・講演概要集, May 2013, Japanese, Domestic conference

    Oral presentation

  • サブメソスケール乱流混合による琉球諸島周辺海域への黒潮系水塊の波及効果について

    Kamidaira, Y, Uchiyama, Y

    土木学会関西支部年次学術講演会・講演概要集, May 2013, Japanese, Domestic conference

    Oral presentation

  • Initial oceanic dispersion mechanism of radionuclides released from Fukushima

    Uchiyama, Y, Yamanishi, T, Tsumune, D, Miyazawa, Y

    Japan Geoscience Union Meeting 2013, May 2013, English, Chiba, Japan, International conference

    Oral presentation

  • 流路変動に伴う黒潮系水塊の瀬戸内海への波及について

    Kuriyama, T, Uchiyama, Y, Miyazawa, Y

    2013年度日本海洋学会春季大会・講演要旨集, Mar. 2013, Japanese, TUMSAT, Tokyo, Japan, Domestic conference

    Oral presentation

  • 超高解像度3次元海洋モデルによる砕波帯‐陸棚相互作用の解析

    Kaida, H, Uchiyama, Y, McWilliams, J

    2013年度日本海洋学会春季大会・講演要旨集, Mar. 2013, Japanese, TUMSAT, Tokyo, Japan, Domestic conference

    Oral presentation

  • 黒潮続流フロント周辺におけるサブメソスケール渦の発生機構

    Ishii, S, Uchiyama, Y, Miyazawa, Y

    2013年度日本海洋学会春季大会・講演要旨集, Mar. 2013, Japanese, TUMSAT, Tokyo, Japan, Domestic conference

    Oral presentation

  • Typhoons alter dispersal patterns in the Kuroshio Current system

    Mitarai, S, Uchiyama, Y, Sakagami, T, Molemaker, M.J, Siegel, D.A, McWilliams, J

    ASLO Aquatic Sciences Meeting 2013, Feb. 2013, English, New Orleans, LA, USA, International conference

    Invited oral presentation

  • Submesoscale Frontal Dynamics in the Kuroshio Extension Jet

    Ishii, S, Uchiyama, Y, Miyazawa, Y

    AGU Fall Meeting 2012, Dec. 2012, English, San Francisco, CA, USA, International conference

    Oral presentation

  • Impact of the Kurishio paths on oceanic and estuarine circulations in and around Seto Inland Sea, Japan

    Kuriyama, T, Uchiyama, Y, Miyazawa, Y

    AGU Fall Meeting 2012, Dec. 2012, English, San Francisco, CA, USA, International conference

    Oral presentation

  • Coastal dispersal of radionuclides released from the Fukushima Nuclear Power Plant

    Uchiyama, Y, Ishii, T, Tsumune, D, Miyazawa, Y

    AGU Fall Meeting 2012, Dec. 2012, English, San Francisco, CA, USA, International conference

    Oral presentation

  • A method to characterize the spatial structure of superdepth-scale near-bank vortices, with a view to operational monitoring

    Wells, J.C, Miyazawa, Y, Phan, T.N.M, Nguyen, L.V, Susuki, Y, Kirkey, W.D, Islam, M.S, Fuller, C.B, Bonner, J.S, Uchiyama, Y

    1st International Conference on Frontiers in Computational Physics: Modeling the Earth System, Dec. 2012, English, Boulder, CO, USA, International conference

    Oral presentation

  • 黒潮続流域におけるフロント不安定とサブメソスケール乱流への遷移について

    Uchiyama, Y, Ishii, S, Miyazawa, Y

    日本流体力学会年会2012講演論文集, Sep. 2012, Japanese, Domestic conference

    Oral presentation

  • Transient thermal plume dispersal in the Hudson River estuary

    Uchiyama, Y, Ishii, S, Phan, T.M, Wells, J, Islam, M, Kirkey, W, Bonner, J

    ASLO Aquatic Sciences Meeting 2012, Jul. 2012, English, Otsu, Japan, International conference

    Oral presentation

  • Oceanic circulations in the Southern California Bight from a multi-nested high-resolution forward model

    Uchiyama, Y

    International Symposium on Watercourse Sensing and Operational Monitoring, Jul. 2012, English, Otsu, Japan, International conference

    [Invited]

    Invited oral presentation

  • Interaction between the Kuroshio intrusion and intrinsic variability in Seto Inland Sea, Japan

    Kuriyama, T, Uchiyama, Y, Miyazawa, Y

    ASLO Aquatic Sciences Meeting 2012, Jul. 2012, English, Otsu, Japan, International conference

    Oral presentation

  • A downscaling experiment on reproducibility of the Kuroshio off Japan

    Ishii, S, Uchiyama, Y, Miyazawa, Y

    ASLO Aquatic Sciences Meeting 2012, Jul. 2012, English, Otsu, Japan, International conference

    Oral presentation

  • 離岸流の発達に及ぼす流れから波へのフィードバック機構の影響

    Kaida, H, Uchiyama, Y

    土木学会関西支部年次学術講演会・講演概要集, May 2012, Japanese, Domestic conference

    Oral presentation

  • 福島第一原子力発電所から漏洩した放射性物質の海洋分散特性

    Ishii, T, Uchiyama, Y

    土木学会関西支部年次学術講演会・講演概要集, May 2012, Japanese, Domestic conference

    Oral presentation

  • 高解像度領域海洋モデルを用いた沿岸海洋流動に及ぼす波浪の影響に関する研究

    Nishii, T, Uchiyama, Y

    土木学会関西支部年次学術講演会・講演概要集, May 2012, Japanese, Domestic conference

    Oral presentation

  • Three-dimensional unsteady wave-driven littoral currents

    Uchiyama, Y, McWilliams, J

    4th International Workshop on Modeling the Ocean (IWMO-2012), May 2012, English, Yokohama, Japan, International conference

    Oral presentation

  • Oceanic responses to surface gravity waves in the Southern California Bight

    Nishii, T, Uchiyama, Y, McWilliams, J

    4th International Workshop on Modeling the Ocean (IWMO-2012), May 2012, English, Yokohama, Japan, International conference

    Poster presentation

  • Oceanic dispersion of cesium-137 off the north-eastern Pacific coast of Japan

    Ishii, T, Uchiyama, Y, Tsumune, D, Miyazawa, Y

    4th International Workshop on Modeling the Ocean (IWMO-2012), May 2012, English, Yokohama, Japan, International conference

    Poster presentation

  • Effects of wave-current interaction on development of rip currents

    Kaida, H, Uchiyama, Y

    4th International Workshop on Modeling the Ocean (IWMO-2012), May 2012, English, Yokohama, Japan, International conference

    Poster presentation

  • 東北・北関東太平洋沿岸域における放射性物質の海洋分散

    Uchiyama, Y, Ishii, T, Tsumune, D, Miyazawa, Y

    2012年度日本海洋学会春季大会・講演要旨集, Mar. 2012, Japanese, Tsukuba, Ibaragi, Japan, Domestic conference

    Oral presentation

  • 瀬戸内海流動シミュレーションの高精度化に向けたダウンスケーリングによる黒潮流動のモデリング

    Kuriyama, T, Uchiyama, Y, Miyazawa, Y

    2012年度日本海洋学会春季大会・講演要旨集, Mar. 2012, Japanese, Tsukuba, Ibaragi, Japan, Domestic conference

    Oral presentation

  • ROMS を用いた黒潮の流況再現とダウンスケーリング効果の検証

    Ishii, S, Uchiyama, Y, Miyazawa, Y

    2012年度日本海洋学会春季大会・講演要旨集, Mar. 2012, Japanese, Tsukuba, Ibaragi, Japan, Domestic conference

    Oral presentation

  • Nearshore dispersion of the radioactive cesium 137 leaked from the Fukushima I Power Plant

    Uchiyama, Y, Ishii, T

    The Third Korea-Japan Mini Symposium on Modeling and Measurements of Hydraulic Flows, Mar. 2012, English, 神戸大学大学院工学研究科市民工学専攻, Department of Civil Engineering, Kobe University, International conference

    Oral presentation

  • Highly-resolved computations in the Hudson River Estuary

    Phan, T.M, Uchiyama, Y, Bonner, J, Ojo, T, Wells, J, Fuller, C, Islam, M, Kirkey, W, Ishii, S, Nishii, T

    Ocean Sciences Meeting, Feb. 2012, English, Salt Lake City, UT, USA, International conference

    Poster presentation

  • 多段ネスティングを用いた高解像度領域海洋循環モデルによるサブメソスケール分散について

    Uchiyama, Y, McWilliams, J

    2011年度日本海洋学会秋季大会・講演要旨集, Sep. 2011, Japanese, Fukuoka, Japan, Domestic conference

    Oral presentation

  • Wave-current interaction in a three-dimensional oceanic circulation model based on a vortex-force formalism: Applications to the surf-zone and inner-shelf circulations

    Uchiyama Yusuke

    Ocean Sciences Meeting 2010, Feb. 2010, English, American Geophysical Union, Portland, OR, USA, International conference

    [Invited]

    Invited oral presentation

  • Non-tidal Variability in Semidiurnal Internal Tide Generation in the Southern California Bight

    Hill-Lindsay C, Buijsman M.C, Uchiyama Yusuke

    Ocean Sciences Meeting 2010, Feb. 2010, English, American Geophysical Union, Portland, OR, USA, International conference

    Poster presentation

  • Applications of Regional Ocean Modeling System (ROMS) for surf zone environment

    Voulgaris G, Kumar N, Warner J.C, Haas K.A, Uchiyama Yusuke

    Ocean Sciences Meeting 2010, Feb. 2010, English, American Geophysical Union, Portland, OR, USA, International conference

    Poster presentation

  • Wave-current interaction in ROMS: A vortex-force formalism

    Uchiyama Yusuke

    2009 ROMS/TOMS Asia-Pacific Workshop, 2009, English, University of New South Wales, Sydney, Australia, International conference

    Oral presentation

  • Ensemble Data Assimilation for Idealized California Current System with ROMS-LETKF

    Miyoshi T, Ide K, McWilliams J.C, Li Z, Uchiyama Yusuke

    The 5th WMO Symposium on Data Assimilation, 2009, English, WMO, Melbourne, Australia, International conference

    Oral presentation

  • Submesoscale instability in subtidal inner shelf circulation off Palos Verdes, California

    Uchiyama Yusuke

    Ocean Sciences Meeting 2008, Feb. 2008, English, American Geophysical Union, Orlando, FL, USA., International conference

    Oral presentation

  • A high- resolution nested simulation on non-cohesive suspended sediment transport around Palos Verdes, California

    Uchiyama Yusuke

    2007 ROMS/TOMS Users Workshop, 2007, English, UCLA, Los Angeles, CA, USA, International conference

    Oral presentation

  • Simulating forced infragravity long-waves with ROMS

    Uchiyama Yusuke

    Ocean Sciences Meeting 2006, Feb. 2006, English, American Geophysical Union, Honolulu, HI, USA., International conference

    Oral presentation

  • Infragravity waves forced by surface wind waves in the central North Pacific Ocean

    Uchiyama Yusuke

    2005 ROMS/TOMS Users Workshop, 2005, English, Scripps Institute of Oceanography, La Jolla, CA, USA., International conference

    Oral presentation

  • Intertidal sediment transport and morphological response in San Francisco Bay using modefied Princeton Ocean Model

    Uchiyama Yusuke

    AGU Chapmen Conference on Salt Marsh Geomorphology: Physical and Ecological Effects on Landform, 2004, English, American Geophysical Union, Halifax, NS, Canada, International conference

    Poster presentation

  • Modeling wetting and drying process in San Francisco Bay using the Princeton Ocean Model

    Uchiyama Yusuke

    AGU Fall Meeting 2003, Dec. 2003, English, American Geophysical Union, San Francisco, CA, USA, International conference

    Poster presentation

  • Near-bed velocity and turbidity measurements at an intertidal estuarine sand-flat influenced by fluvial discharges

    Uchiyama Yusuke

    EGS-AGU-EUG Joins Assembly, Apr. 2003, English, European Geophysical Society, Nice, France, International conference

    Poster presentation

  • Hydrodynamic, sedimentological and morphological processes on Banzu intertidal sand-flat, Tokyo Bay, Japan

    Uchiyama Yusuke

    AGU Spring Meeting 2002, May 2001, English, American Geophysical Union, Washington DC, USA, International conference

    Oral presentation

  • Coastal groundwater flow and associated nutrient transport into the sea

    Uchiyama Yusuke

    2nd Joint Meeting of the Coastal Environmental Science and Technology (CEST) Panel, 1999, English, UJNR, Washington DC, USA, International conference

    Oral presentation

  • A robust regional downscaling ocean modeling for the Kuroshio region off Japan

    Uchiyama, Y

    Ocean Sciences Meeting 2020, San Diego, CA, USA., English

    [Invited]

    Invited oral presentation

  • Effects of Wave Streaming and Wave Variations on Nearshore Wave-driven Circulation

    Wang, P, McWilliams, J.C, Uchiyama, Y, Chekroun, M

    Ocean Sciences Meeting 2020, San Diego, CA, USA., English

    Oral presentation

  • Biogeochemical responses to seasonal oceanic variability around a ridge area along the Kuroshio off Japan

    Zhang, X, Uchiyama, Y, Suzue, Y, Yamazaki, H

    Ocean Sciences Meeting 2020, San Diego, CA, USA., English

    Poster presentation

  • Identification of coral spawn supply source for restoration of the Sekisei Lagoon within the Kuroshio region

    Kashima, M, Takeda, N, Odani, S, Uchiyama, Y, Kamidaira, Y, Mitarai, S

    AGU Fall Meeting 2019, San Francisco, CA, USA, English

    Poster presentation

  • How the Kuroshio enriches the southern coast of Japan and its downstream regions?

    Nagai, T, Duran, S, Otero, D, Yoshie, N, Ohgi, K, Hasegawa, D, Clayton, S, Uchiyama, Y

    PICES-2019 – Connecting Science and Communities in a Changing North Pacific, Victoria, BC, Canada, English

    Oral presentation

  • 沖縄本島周辺海域におけるラグランジュ粒子追跡によるサンゴ浮遊幼生のコネクティビティ数値解析

    内山雄介, 小谷瑳千花, 宮川 翼

    2019年度日本海洋学会秋季大会,富山国際会議場, Japanese

    Oral presentation

  • Mass and Heat Transport Generated by the Kuroshio and Tides Investigated with a High Resolution Downscaled Regional Oceanic Model

    Masunaga, E, Kimura, W, Kosako, T, Uchiyama, Y

    AOGS 16th Annual Meeting (AOGS 2019), Singapore, English

    Oral presentation

  • Medium-term water mass exchange and associated regional circulations in the South China Sea

    Takaura, N, Uchiyama, Y, Nizamani, Z, Nakayama, A

    AOGS 16th Annual Meeting (AOGS 2019), Singapore, English

    Oral presentation

  • A flood-induced sediment and suspended radiocesium transports in the Fukushima Coast due to Typhoon 201326 analyzed with a JCOPE2-ROMS downscaling model and in situ observations

    Tokunaga, N, Uchiyama, Y, Tsumune, D, Yamada, M, Tateda, Y, Ito, Y, Ishimaru, T, Watanabe, Y, Ikehara, K, Fukuda, M

    AOGS 16th Annual Meeting (AOGS 2019), Singapore, English

    Oral presentation

  • Kuroshio-derived pinch-off mesoscale eddies: Generation, propagation, and recollision with the Kuroshio

    Uchiyama, Y, Okada, N, Dong, C

    AOGS 16th Annual Meeting (AOGS 2019), Singapore, English

    Oral presentation

  • Biogeochemical responses to seasonal oceanic variability along the Kuroshio

    Zhang, X, Uchiyama, Y, Suzue, Y, Yamazaki, H

    AOGS 16th Annual Meeting (AOGS 2019), Singapore, English

    Oral presentation

  • Eddy-induced transports and meso- and submesoscale dynamics in coastal and shelf seas

    Uchiyama, Y.

    Gordon Research Conference - Coastal Ocean Dynamics, Southern New Hampshire University, NH, USA., English

    [Invited]

    Invited oral presentation

  • Implementing regional downscaling capability in the STREAMER ocean prediction system based on multi-nested ROMS model(多段ネストROMSモデルに基づいたSTEAMERにおけるダウンスケーリング機能の実装)

    Kamidaira, Y, Kawamura, H, Kobayashi, T, Uchiyama, Y

    Japan Geoscience Union Meeting 2019 (JpGU 2019), Chiba, Japan, Japanese

    Oral presentation

  • Transport processes around the Izu-chain islands investigated with a Lagrangian particle tracking model(Lagrange粒子追跡モデルを用いた伊豆諸島周辺海域の物質輸送・拡散の評価)

    Kimura, W, Masunaga, E, Kosako, T, Uchiyama, Y

    Japan Geoscience Union Meeting 2019 (JpGU 2019), Chiba, Japan, Japanese

    Oral presentation

  • Multiscale routes to supply nutrients through the Kuroshio nutrient stream

    Nagai, T, Clayton, S, Uchiyama, Y

    Japan Geoscience Union Meeting 2019 (JpGU 2019), Chiba, Japan, English

    Oral presentation

  • A reanalysis of regional circulations in the Southern South China Sea using a HYCOM-ROMS downscaling ocean model(HYCOM-ROMSモデルを用いた南シナ海南部における海洋流動構造に関する研究)

    Takaura, N, Uchiyama, Y, Nizamani, Z, Nakayama, A

    Japan Geoscience Union Meeting 2019 (JpGU 2019), Chiba, Japan, Japanese

    Oral presentation

  • Neasrshore transport of suspended radiocesium In the Fuksima Coast derived from Niida River induced by Typhoon Wipha(新田川河口海域における台風Wilpaによる出水イベントに伴う懸濁態放射性セシウムの沿岸輸送について)

    Tokunaga, N, Uchiyama, Y, Tsumune, D, Yamada, M, Tateda, Y, Ito, Y, Ishimaru, T, Watanabe, Y, Ikehara, K, Fukuda, M

    Japan Geoscience Union Meeting 2019 (JpGU 2019), Chiba, Japan, Japanese

    Oral presentation

  • Fates and dynamical roles of pinch-off mesoscale eddies originated from the Kuroshio Extension Jet(黒潮続流ジェットから放出される切離中規模渦の挙動と力学的効果について)

    Uchiyama, Y, Okada, N, Dong, C

    Japan Geoscience Union Meeting 2019 (JpGU 2019), Chiba, Japan, English

    Oral presentation

  • Biogeochemical responses to seasonal oceanic variability along the Kuroshio

    Zhang, X, Uchiyama, Y, Suzue, Y, Yamazaki, H

    Japan Geoscience Union Meeting 2019 (JpGU 2019), Chiba, Japan, English

    Oral presentation

  • A Post-disaster Assessment on a Storm-induced Flood and Associated Coastal Dispersal of the River-derived Suspended Radiocesium Originated from the Fukushima Nuclear Accident

    Yusuke Uchiyama

    2nd International Conference on Civil and Environmental Engineering (ICCEE2022), 05 Jan. 2022, English

    [Invited]

    Keynote oral presentation

Association Memberships

  • The Meteorological Society of Japan

    Apr. 2012 - Mar. 2022
  • Asia Oceania Geosciences Society

  • Japan Geoscience Union

  • American Geophysical Union

  • The Oceanographic Society of Japan

  • Japan Society of Civil Engineers

Research Projects