Directory of Researchers

NAKAYAMA Keisuke
Graduate School of Engineering / Department of Civil Engineering
Professor
Civil Engineering / Architecutre and planning / Building Engineering
Last Updated :2022/08/06

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

  • ecology
  • hydrology
  • green house effect gas
  • internal wave
  • stratification

Research Areas

  • Social infrastructure (civil Engineering, architecture, disaster prevention) / Hydroengineering

Committee Memberships

  • Jun. 2019 - Present, 土木学会, 気候変動適応研究推進小委員会 委員長
  • Apr. 2019 - Present, 環境省, 気候変動適応近畿広域協議会委員
  • 2019 - Present, 国土交通省, 温暖化適応策創生・実装連携会委員
  • Apr. 2018 - Present, 島根大学, 島根大学研究推進協議会委員
  • Apr. 2017 - Mar. 2019, 環境省, 地域適応コンソーシアム近畿委員
  • Apr. 2016 - Present, 国土交通省, 河川懇談会委員
  • Apr. 2016 - Mar. 2018, 大阪府, 「豊かな大阪湾」創出手法に関する懇話会委員
  • Jun. 2015 - Present, 土木学会水工学委員会 委員
  • Jun. 2015 - May 2017, 土木学会, 水工学委員会 幹事長
  • Jun. 2013 - May 2018, 土木学会, 海岸工学委員会 幹事
  • Jun. 2013 - May 2018, 土木学会, 海岸工学委員会 波動小委員会 副小委員長
  • Apr. 2013 - Present, マリモ科学委員会 委員
  • Apr. 2008 - Present, 国土交通省, 釧路湿原水循環小委員会 委員

Awards

  • 2010 北海道開発協会長賞

  • 2006 Award on the United Nations Atlas Book

  • 2005 Gledden Senior Fellowship Award

  • 1998 平成9年度水工学論文奨励賞

  • 1998 平成10年度水文水資源学会ポスター賞

  • 1995 平成7年度土木学会年次学術講演会優秀講演者賞

  • 1992 吉町先生記念賞

  • 1992 廣井勇記念賞

Published Papers

  • Keisuke Nakayama, Hidekazu Tsuji

    Aug. 2021, Physics of Fluids

    Scientific journal

  • Keisuke Nakayama, Ryo Iwata, Tetsuya Shintani

    Elsevier {BV}, Jun. 2021, Ocean Engineering, 230, 108884 - 108884

    Scientific journal

  • Wataru Ito, Keisuke Nakayama, Tetsuya Shintani

    Informa {UK} Limited, 24 Apr. 2021, Coastal Engineering Journal, 1 - 14

    Scientific journal

  • Hao‐Chi Lin, Chih‐Yu Chiu, Jeng‐Wei Tsai, Wen‐Cheng Liu, Kazufumi Tada, Keisuke Nakayama

    American Geophysical Union ({AGU}), 18 Apr. 2021, Journal of Geophysical Research: Biogeosciences

    Scientific journal

  • Katsuaki KOMAI, Tatsuya SATO, Toshiyuki CHIBA, Keisuke NAKAYAMA

    In present study, the effect of the seasonal difference in photosynthetic activity of eelgrass on the absorption/release characteristics of dissolved inorganic carbon was clarified from the results of model analysis of changes in dissolved inorganic carbon by aquatic tank experiments using eelgrass and chlorophyll-a content analysis. It was revealed that the optimum value of the maximum photosynthetic rate for dissolved inorganic carbon by eelgrass varies depending on the season of the experiment. From the estimated values by the model and the results of the chlorophyll-a content of eelgrass, it was suggested that the difference in the growth stage of eelgrass affected the photosynthetic activity and the maximum photosynthetic rate. The results obtained based on the measured values of the detailed specifications of eelgrass were applied to the model to clarify the relationship between the characteristics of the vertical profile of dissolved inorganic carbon and the branching structure of eelgrass.

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 77 (2), I_565 - I_570, Japanese

  • Hiroki MATSUMOTO, Keisuke NAKAYAMA, Katsuaki KOMAI, Kazufumi TADA, Hao-Chi LIN, Tetsuya SHINTANI

    This study investigated the effect of eelgrass respiration and photosynthesis on DIC's horizontal distribution at Lake Komuke in northeastern Hokkaido using a newly extended SAV model (Submerged Aquatic vegetation model). The original SAV model successfully predicts the interaction between fluid and vegetation, however it needs enormous computational resources for field scale simulations. Therefore, the Super SAV model, which integrates a few hundred SAVs into only one SAV, was proposed in this study. The Super SAV model was validated by comparing the velocity field and diffusion coefficient with the original SAV model under a current uniform condition. The Super SAV model, which considers respiration and photosynthesis by eelgrass, was incorporated into a three-dimensional hydrodynamic model. The results obtained by the Super SAV model was demonstrated to agree with the observed data in Lake Komuke.

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 77 (2), I_613 - I_618, Japanese

  • K. Nakayama, K. G. Lamb

    25 Nov. 2020, Journal of Fluid Mechanics

    [Refereed]

    Scientific journal

  • K. Nakayama, T. Sato, K. Tani, L. Boegman, I. Fujita, T. Shintani

    American Geophysical Union ({AGU}), 29 Oct. 2020, Journal of Geophysical Research: Oceans, 125 (10)

    [Refereed]

    Scientific journal

  • EVALUATION OF HYDRODYNAMIC EFFECTS ON BLUE CARBON DYNAMICS IN THE YATSUSHIRO SEA

    Bing Xiong, Naoki Saito, Hiroto Komori, Shinichiro Yano, Keisuke Nakayama, Katsuaki Komai, Kei Yajima

    Sep. 2020, Proc. 22nd Int. Conf. on IAHR-APD, 1 - 6

    [Refereed]

  • FIELD OBSERVATION ON BLUE CARBON DYNAMICS IN THE YATSUSHIRO SEA CONSIDERING INFLUENCE OF STRATIFICATION

    Naoki Saito, Xion Bing, Hiroto Komori, Shinichiro Yano, Keisuke Nakayama, Katsuaki Komai, Kei Yajima

    Sep. 2020, Proc. 22nd Int. Conf. on IAHR-APD, 1 - 6

    [Refereed]

  • APPLICATION OF OPTICAL FLOW TECHNIQUES FOR RIVER SURFACE FLOW MEASUREMENTS

    Jumpei Yagi, Kojiro Tani, Ichiro Fujita, Keisuke Nakayama

    Sep. 2020, Proc. 22nd Int. Conf. on IAHR-APD, 1 - 6

    [Refereed]

  • DISCHARGE ESTIMATION BY STIV COMBINED WITH THE MAXIMUM ENTROPY METHOD

    Takuya Hamada, Ichiro Fujita, Kojiro Tani, Keisuke Nakayama

    Sep. 2020, Proc. 22nd Int. Conf. on IAHR-APD, 1 - 6

    [Refereed]

  • K. Nakayama, T. Shintani, K. Komai, Y. Nakagawa, J. W. Tsai, D. Sasaki, K. Tada, H. Moki, T. Kuwae, K. Watanabe, M. R. Hipsey

    American Geophysical Union ({AGU}), 03 Aug. 2020, Water Resources Research, 56 (8)

    [Refereed]

    Scientific journal

  • Empirical Approach for Modeling of Partition Coefficient on Lead Concentrations in Riverine Sediment

    Saadia Bouragba, Katsuaki Komai, Keisuke Nakayama

    Jul. 2020, International Journal of Environmental Science and Development, 11 (7), 352 - 357, English

    [Refereed]

    Scientific journal

  • Nakayama, K., Komai, K., Tada, K., Lin, H.C., Yajima, H., Yano, S., Hipsey, M.R., Tsai, J.W.

    Elsevier {BV}, 2020, Ecological Modelling, 431, 109188 - 109188

    [Refereed]

    Scientific journal

  • Chiu, C.-Y., Jones, J.R., Rusak, J.A., Lin, H.-C., Nakayama, K., Kratz, T.K., Liu, W.-C., Tang, S.-L., Tsai, J.-W.

    Elsevier {BV}, 2020, Science of the Total Environment, 717, 137052 - 137052

    [Refereed]

    Scientific journal

  • Sakaguchi, S., Nakayama, K., Kobayashi, K., Komai, K.

    In Kushiro River basin, inundation is likely to occur due to heavy rain, since the river-bed slope is very gentle in the downstream portion, which has natural levees. Consequently, in past floods, river discharge was observed to increase slowly and a delay of a few days in peak river discharge was observed compared to the peak precipitation. Therefore, we applied a distributed hydrological model, Geophysical fluid CIRCulation model (GeoCIRC), to reproduce such flood discharge in Kushiro River. GeoCIRC is based on object-oriented programming and various hydrological processes, such as infiltration flow, underground water flow, surface flow, and river flow can be implemented easily. We proposed a model that can incorporate the effect of return flow using storage function by introducing new parameters, such as storage time and time lag. This was done to consider not only the flood inundation in Kushiro River but also the return flow from flood inundation to the river flow. As a result, we obtained high Nash-Sutcliffe coefficients for river discharge for two large flood events.

    Japan Society of Hydrology and Water Resources (JSHWR) / Japanese Association of Groundwater Hydrology (JAGH) / Japanese Association of Hydrological Sciences (JAHS) / Japanese Society of Physical Hydrology (JSPH), 2020, Hydrological Research Letters, 14 (2), 75 - 80, English

    [Refereed]

    Scientific journal

  • Sakaguchi, S., Nakayama, K., Vu, T.T.T., Komai, K., Nielsen, P.

    This study aims to develop a new wave equation model by modifying the Fully-nonlinear and strongly-Dispersive Surface wave (FDS) equations. The modification was performed by applying a new expansion in a series of the vertical coordinate, z(mu), to the velocity potential while a simple expansion in a series of z was applied to the FDS equations. Verification of the model was conducted by comparing with the theoretical solutions of surface solitary waves. We applied the modified FDS equations to wave fields over a bump under conditions with and without currents, which agreed very well with the time series of wave heights and velocity obtained from laboratory experiments. The dispersion relationship computed using the normalized modified FDS equations also agreed very well with the theoretical solution when we gave the number of expansion terms as 3 with mu = 2.5. Additionally, the profile of surface waves computed with the modified FDS equation was shown to have a larger width ridge, a bulbous-type wave, by comparing with a Trochoidal wave under the condition of waves against a current.

    Informa {UK} Limited, 2020, Coastal Engineering Journal, 62 (2), 159 - 169, English

    [Refereed]

    Scientific journal

  • Hiroki MATSUMOTO, Keisuke NAKAYAMA, Katsuaki KOMAI, Kazufumi TADA, Daisuke SASAKI, Kenta WATANABE, Atsushi KUBO, Yasuyuki MARUYA

    In order to reveal the carbon uptake mechanism of eelgrass, the vertical distribution of dissolved inorganic carbon (DIC) was estimated by a conceptual model considering the stratification effect at Lake Komuke. The field observation show that the eelgrass meadows change stratification and the vertical distribution of DIC. The conceptual model was verified by comparing with the vertical diffusion coefficients obtained from the Submerged Aquatic Vegetation model (SAV model). As a result, the conceptual model results agreed with the SAV model when eelgrass exists densely in a strong stratified fluid. Additionally, SAV model was improved in order to reduce run-time cost by combining with a hydrostatic model. The improved SAV model shows high accuracy and the run time was reduced dramatically.

    Japan Society of Civil Engineers, 2020, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 76 (2), I_869 - I_874, Japanese

  • SAITO Naoki, XIONG Bing, KOMORI Hiroto, YANO Shinichiro, NAKAYAMA Keisuke, KOMAI Katsuaki, YAJIMA Hiroshi

     "Blue carbon", which is carbon fixed by marine organisms, is attracting attention as a new measure to reduce atmospheric CO2. We carried out field survey regarding the CO2 partial pressure (pCO2) in sea water in the Yatsushiro Sea where it is confirmed that habitats of corals and seagrass, in order to reveal the pCO2 dynamics in actual situation. Moreover, by observation under different mixing conditions, we tried to reveal how stratification can affect on the dynamics. As a result, it was confirmed that with the development of strong stratification, the effect of photosynthesis by phytoplankton was concentrated on the surface and pCO2 decreased. In addition, it was suggested that the influx of water affected by corals caused the fluctuation of pCO2. Finally, trial calculation of CO2 flux between sea and air in daytime shows that the Yatshiro Sea can absorb CO2 throughout the year, regardless of the mixing conditions.

    Japan Society of Civil Engineers, 2020, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 76 (2), I_901 - I_906, Japanese

  • CLASSIFICATION OF INTERNAL WAVE BREAKING OVER A SLOPE WITH THE CHANGE IN THE THICKNESS OF PYCNOCLINE

    岩田 遼, 佐藤 啓央, 中山 恵介

    土木学会, Nov. 2019, 水工学論文集 Annual journal of Hydraulic Engineering, JSCE, 64, I_769 - 774, Japanese

    [Refereed]

  • RESONANT CHARACTERISTICS OF TRIANGULAR WAVE SEQUENCE OVER SHALLOW FLOW WITH SPARSELY DISTRIBUTED STRIP ROUGHNESS

    東川 真也, 藤田 一郎, 中山 恵介, 谷 昂二郎

    土木学会, Nov. 2019, 水工学論文集 Annual journal of Hydraulic Engineering, JSCE, 64, I_445 - 450, Japanese

    [Refereed]

  • ESTIMATION OF ROTATION ANGLE AND CRITICAL VELOCITY OF MARIMOS DUE TO WAVES AND CURRENTS

    Noriko HAYASHI, Keisuke NAKAYAMA, Yoichi OYAMA, Katsuaki KOMAI

    Nov. 2019, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 75 (2), I_775 - I_780, Japanese

    [Refereed]

    Scientific journal

  • MEASUREMENT OF SEAGRASS DISTRIBUTION BY SATELLITE DATA AND VARIDATION USING DISSOLVED INORGANIC CARBON IN LAGOON

    Katsuaki KOMAI, Hiroshi HAYAKAWA, Tatsuya SATO, Keisuke NAKAYAMA

    Seagrass distribution in a lagoon located near the Sea of Okhotsk was estimated from satellite data, and varidated using DIC and its variation obtained by field observation data. Seagrass distribution was made by converted data from averaged NDVI of satellite Sentinel-2 to seagrass vegetation density. As a result of calculation of DIC model, since field observation data at 17 points in/out of seagrass vegetation area for a period of from July to August in 2018 were successfully represented, seagrass distribution using satellite NDVI was well verified. Bias of calculation results were appeared due to seagrass existence, however, the estimation insufficiency of vegetation under the water and the influence of hydraulic re-sistance of seagrass to tidal current and water quality were likely associated.

    Nov. 2019, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 75 (2), I_397 - I_402, Japanese

    [Refereed]

    Scientific journal

  • TADA Kazufumi, NAKAYAMA Keisuke, NAKANISHI Yutaro, SASAKI Daisuke, KOMAI Katsuaki

    Japan Society of Civil Engineers, Oct. 2019, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 75 (2), I_25 - 30, Japanese

    [Refereed]

  • KENICHIRO KOBAYASHI, RYO KAWASAKI, ICHIRO FUJITA, KEISUKE NAKAYAMA

    The International Association for Hydro-Environment Engineering and Research (IAHR), 01 Sep. 2019, 38th IAHR World Congress - "Water: Connecting the World"

    International conference proceedings

  • Residence time in a lagoon system

    K. Yamamoto, N. Hayashi, K. Nakayama, J.W. Tsai, M.C. Hung, S.C. Hsiao

    Sep. 2019, Proc. 10th Int. Conf. on Asian and Pacific Coasts, 10, English

    [Refereed]

    Scientific journal

  • 伊藤航, 中山恵介, 矢野真一郎, 熊柄, 齋藤直輝, 駒井克昭, 矢島啓

     We developed the hydrodynamic model of Yatsushiro Sea in order to analyze stratified flow field and water quality in Yatsushiro Sea. Yatsushiro Sea is connected to Ariake Sea with very narrow strait, which cannot be modelled due to the limitation of computational capacity. Therefore, we made an attempt to develop the SYA (Strait between Yatsushiro Sea and Ariake Sea) model to estimate fluxes of seawater exchange through SYA. It was found that there is no seasonal difference in seawater exchange flux. As a result, field observations were successfully reproduced by applying the SYA model into the Yatsushiro Sea model with good agreements.

    Japan Society of Civil Engineers, Jul. 2019, 土木学会論文集B3(海洋開発), 75 (2), I_977 - I_982, Japanese

    [Refereed]

    Scientific journal

  • 水深葉長比を考慮した有効水草高さに関する検討

    佐々木大輔, 中山恵介, 中西佑太郎, 中川康之, 田多一史, 駒井克昭

    Jul. 2019, 土木学会論文集B3(海洋開発), 75 (2), I_504 - I_509, Japanese

    [Refereed]

    Scientific journal

  • Nakayama, K., Sato, T., Shimizu, K., Boegman, L.

    2019, Physical Review Fluids, 4 (1), 014801, English

    [Refereed]

    Scientific journal

  • Nakayama, K., Kakinuma, T., Tsuji, H.

    2019, European Journal of Mechanics, B/Fluids, 74, 81 - 91, English

    [Refereed]

    Scientific journal

  • Nakaegawa, T., Pinzon, R., Fabrega, J., Cuevas, J.A., de Lima, H.A., Cordoba, E., Nakayama, K., Lao, J.I.B., Melo, A.L., Gonzalez, D.A., Kusunoki, S.

    2019, PLoS ONE, 14 (12), English

    [Refereed]

    Scientific journal

  • Bouragba, S., Komai, K., Nakayama, K.

    2019, Water Science and Technology, 80 (1), 11 - 24, English

    [Refereed]

    Scientific journal

  • 貯水池底層における貧酸素水塊発生機構の解明

    山元幸之助, NAKAYAMA KEISUKE, 藤井智康, 藤原建紀, 清水武俊, KOBAYASHI KENICHIRO

    Dec. 2018, 土木学会論文集B1(水工学), 74 (5), I - 535-I_540, Japanese

    [Refereed]

    Scientific journal

  • 浅水流方程式・局所慣性方程式の精度検証と最適空間解像度に関する検討

    KOBAYASHI KENICHIRO, NAKAYAMA KEISUKE, 阪口詩乃

    Dec. 2018, 土木学会論文集B1(水工学), 74 (5), I - 1513-I_1518, Japanese

    [Refereed]

    Scientific journal

  • 洪水氾濫シミュレーションにおいて風の影響を考慮する必要性に関する検討

    KOBAYASHI KENICHIRO, NAKAYAMA KEISUKE, 田中翔, 阪口詩乃, 奥勇一郎, 池内幸司

    Dec. 2018, 土木学会論文集B1(水工学), 74 (5), I - 1459-I_1464, Japanese

    [Refereed]

    Scientific journal

  • 個別要素法を環境流体解析に組み込んだマリモモデルの開発

    林典子, NAKAYAMA KEISUKE, 尾山洋一, 若菜勇, 山田俊郎, 駒井克昭

    Dec. 2018, 土木学会論文集B1(水工学), 74 (5), I - 517-I_522, Japanese

    [Refereed]

    Scientific journal

  • 波・流れ場とアマモ場の相互干渉解析

    中西佑太郎, NAKAYAMA KEISUKE, 中川康之, 茂木博匡, 田多一史, Matthew HIPSEY, 桑江朝比呂

    Nov. 2018, 土木学会論文集B2(海岸工学), 74 (2), I_31 - I_36, Japanese

    [Refereed]

    Scientific journal

  • 二層システムにおける内部ソリトン波の斜面上での砕波形態と物質輸送

    佐藤啓央, NAKAYAMA KEISUKE, 清水健司, Leon BOEGMAN

    Nov. 2018, 土木学会論文集B2(海岸工学), 74 (2), I_655 - I_660, Japanese

    [Refereed]

    Scientific journal

  • 水深が変化する水域を伝播する内部波の数値解析

    越智直人, 柿沼太郎, NAKAYAMA KEISUKE

    Nov. 2018, 土木学会論文集B2(海岸工学), 74 (2), I_25 - I_30, Japanese

    [Refereed]

    Scientific journal

  • 強非線形強分散波動方程式の改良とbumpを有する波動場への適用

    阪口詩乃, NAKAYAMA KEISUKE, Thuy Thi Thu VU, 駒井克昭, Peter NIELSEN

    Nov. 2018, 土木学会論文集B2(海岸工学), 74 (2), I_1 - I_6, Japanese

    [Refereed]

    Scientific journal

  • アマモ場における海水中CO2分圧モデルの開発

    田多一史, NAKAYAMA KEISUKE, 桑江朝比呂

    Nov. 2018, 土木学会論文集B2(海岸工学), 74 (2), I_1237 - I_1242, English

    [Refereed]

    Scientific journal

  • 成層を考慮したアマモ場における溶存無機炭素の変動解析

    田多一史, NAKAYAMA KEISUKE, 駒井克昭, Jeng-Wei Tsai, 佐藤之信, 桑江朝比呂

    Jul. 2018, 土木学会論文集B3(海洋開発), 74 (2), I_444 - I_449, Japanese

    [Refereed]

    Scientific journal

  • 千刈貯水池を対象とした出水時の成層場に関する検討

    NAKAYAMA KEISUKE, 藤原建紀, 藤井智康, 小林健一郎, 中島祐輔

    Mar. 2018, 土木学会論文集B1(水工学), 74 (4), I - 355-I_360, Japanese

    [Refereed]

    Scientific journal

  • 解析解を利用した準長波方程式による洪水氾濫解析

    阪口詩乃, NAKAYAMA KEISUKE, 小林健一郎

    Mar. 2018, 土木学会論文集B1(水工学), 74 (4), I - 1423-I_1428, Japanese

    [Refereed]

    Scientific journal

  • イオンクロマトグラフィーを利用したBayesian理論による溶存物質の輸送割合推定手法の開発

    駒井克昭, NAKAYAMA KEISUKE, 阪口詩乃

    Mar. 2018, 土木学会論文集B1(水工学), 74 (4), I - 505-I_510, Japanese

    [Refereed]

    Scientific journal

  • ESTIMATION OF DISSOLVED SUBSTANCES TRANSPORT IN KUSHIRO RIVER BASIN USING DISSOLVED ION PATTERN

    Katsuaki KOMAI, Keisuke NAKAYAMA, Shunsuke HIROKI, Shino SAKAGUCHI

    Large amount of nutrient salt and dissolved organic matter is transported from Kushiro River basin to coastal area. In present paper, seasonality of transport ratio in dissolved inorganic matter from upstream catchment to downstream reach was estimated by using multiple regression mothod incorporating Bayesian theory into major ion pattern in stream water. Transport ratios could be well verified and esti-mated in several percent of errors. Seasonality of contribution ratio was clearly observed in comparison with uncertain errors. Ion representing each catchment should be extracted in advance by using statistical test.

    土木学会, 2018, Annual journal of Hydraulic Engineering, JSCE, 62, I_505 - I_510, Japanese

    [Refereed]

    Scientific journal

  • Nakayama, K., Maruya, Y., Matsumoto, K., Komai, K., Kuwae, T.

    2018, Estuarine, Coastal and Shelf Science, 212, 286 - 293, English

    [Refereed]

    Scientific journal

  • 斜面上における内部ソリトン波の砕波形態の分類

    NAKAYAMA KEISUKE, 佐藤啓央, Leon Boegman, Leon Boegman

    Nov. 2017, 土木学会論文集B2(海岸工学), 73 (2), I_31 - I_36, Japanese

    [Refereed]

    Scientific journal

  • 3層系における内部波列による質量輸送速度

    NAKAYAMA KEISUKE, 層系における内部波列による質量輸送速度

    Nov. 2017, 土木学会論文集B2(海岸工学), 73 (2), I_55 - I_60, Japanese

    [Refereed]

    Scientific journal

  • 波・流れ場とアマモの連成モデルの構築

    NAKAYAMA KEISUKE, 中西佑太郎, 中川康之, 茂木博匡, 田多一史, 桑江朝比呂

    Jun. 2017, 土木学会論文集B3(海洋開発), 73 (2), I_821 - I_826, Japanese

    [Refereed]

    Scientific journal

  • Roberts Bank tidal flatにおける干潟内流動と塩分濃度

    NAKAYAMA KEISUKE, 駒井克昭, Robert W. Elner, 桑江朝比呂

    Jun. 2017, 土木学会論文集B3(海洋開発), 73 (2), I_618 - I_623, Japanese

    [Refereed]

    Scientific journal

  • 貯水池における出水時の成層場鉛直混合に関する検討

    NAKAYAMA KEISUKE, 藤原建紀, 藤井智康, 小林健一郎, 中島祐輔, 佐藤啓央

    Mar. 2017, 土木学会論文集B1(水工学), 73 (4), I - 979-I_984, Japanese

    [Refereed]

    Scientific journal

  • 洪水氾濫解析を対象とした浅水流方程式の適用性に関する検討

    小林健一郎, NAKAYAMA KEISUKE, 阪口詩乃

    Mar. 2017, 土木学会論文集B1(水工学), 73 (4), I_1405 - I_1410, Japanese

    [Refereed]

    Scientific journal

  • 蛍光X線分析を利用した細粒土砂の輸送割合と安定同位体比による窒素循環量の推定

    NAKAYAMA KEISUKE, 駒井克昭, 丸谷靖幸, 松本経, 阪口詩乃, 桑江朝比呂

    Mar. 2017, 土木学会論文集B1(水工学), 73 (4), I - 1177-I_1182, Japanese

    [Refereed]

    Scientific journal

  • Heavy metals transport simulation by physically based distributed modeling approach (case of study: Harrash River, Algeria)

    S. Bouragba, K. Komai, K. Nakayama

    Mar. 2017, Annual Journal of Hydraulic Engineering, JSCE, 73 (4), I_1159 - I_1164, English

    [Refereed]

    Scientific journal

  • Shimizu, K., Nakayama, K.

    2017, Journal of Geophysical Research: Oceans, 122 (9), 7449 - 7465, English

    [Refereed]

    Scientific journal

  • TADA Kazufumi, TOKORO Tatsuki, WATANABE Kenta, NAKAYAMA Keisuke, KUWAE Tomohiro

     To investigate the diurnal changes of water CO2 fugacity in urbanized shallow waters, we performed in situ measurements throughout the day in both summer and winter in Hiragata Bay located in Yokohama. We statistically analyzed the observed data set using the structured equation modeling (SEM) and the path analysis. As a result, we found that the diurnal variation in the fugacity of CO2 was largely affected by the TA and DIC changes that are moderated mainly by urban drainage and biological metabolism.

    Japan Society of Civil Engineers, 2017, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 73 (2), I_1297 - I_1302, Japanese

    [Refereed]

    Scientific journal

  • Nakanishi Yutaro, Nakayama Keisuke, Nakagawa Yasuyuki, Tada Kazusi, Mogi Hiromasa, Kuwae Asahiro

    アマモ場内では波・流れの影響を受けて水中の溶存物質が移流拡散しており,アマモと波・流れが相互に影響しあっていることを考慮しつつ,アマモ場内のCO2 の移流拡散を検討することは,現在に至るまで極めて困難であった.しかし,アマモの移動速度に着目し,抗力・浮力・摩擦・弾性体を考慮したアマモのモデルを作成し,波・流れ場とアマモの動きを連成することによって,アマモの形状およびアマモ場における流速を同時に再現することが出来た.アマモモデルをより高精度にするために,アマモの幅に関して1本のアマモをある高さから4本に分かれると考慮して,幅を急に変化させる場合と滑らかに変化させる場合の2種類の考え,それぞれを検証し結果を考察した.結果は,滑らかに幅を変位させたほうが良好であることが分かった.しかし,その効果は一様流において有意であり,振動流では改善効果は小さいことも分かった.

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, 2017, Proceeding of Annual Conference, 30, 93 - 93, Japanese

  • Shino Sakaguchi, Keisuke Nakayama, Kenichiro Kobayashi

    分布型流出モデルを用いて流出解析を行う際,長波方程式を用いる洪水氾濫計算に最も多くの時間を要するため,一般的に現場において再現・予測計算を実施することは困難である.汎用的なPCを利用して現場において解析を容易に実施できるようにするためには,洪水氾濫計算を高速化し,計算負荷を小さくする必要がある.
    そこで本研究では,長波方程式に代わるモデルとして,段波モデル,修正段波モデル,キネマティックウェーブ理論に基づくモデルの3つの簡易洪水氾濫モデルを提案し,それぞれのモデルの再現性の検証を行った.再現性の検証は長波方程式を解いた結果を厳密解として行った.再現性の評価はCoDを用いたフロントの形状,およびフロント位置の比較により行う.
    検証の結果,修正段波モデルを用いた場合が最も再現性が良いことが分かった.また,修正段波モデルを用いて計算を実行するとフロント形状が滑らかになる特徴があり,数値計算上の不安定が生じにくいこともわかった.その理由として,段波の進行に対して逆方向の流速を考慮しているためであると考えることができ,この点でも修正段波モデルは優れたモデルであると言える.
    計算速度は簡易洪水氾濫モデルを用いた計算の場合,厳密解を求める計算と比較して約12倍になった.つまり,実際の洪水氾濫に適用する際にも大きな時間短縮を見込むことができる.
    今後は,今回良い結果が得られたモデルについて粗度の効果及び勾配の効果を考慮できるよう改良し,実際の洪水氾濫計算に適用することを試みる.

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, 2017, Proceeding of Annual Conference, 30, 74 - 74, Japanese

  • Sato Takahiro, Nakayama Keisuke, Shimizu Kenji, Boegman Leon

    沿岸域において,風や潮汐などの外力が与えられると密度界面に内部波が発生し,内部波は内部ソリトン波として安定して進行し,やがて沿岸域の斜面上などで砕波する.その際fission,plunging,collapsing,surgingの4種類の砕波形態が発生することが確認されており,その発生条件は2層システムを考えた場合の密度差,沿岸域の斜面勾配,内部ソリトン波の波高などによって決まる.さらに,過去の研究において,砕波形態が異なることで輸送フラックス等が大きく変化するため,物質輸送のされ方が異なることが示されている.そこで本研究では,物質が貯留されやすいのは密度界面であることを考慮し,砕波形態が異なるときの密度界面における物質輸送の違いを確かめた.主たる結果として,fission,plungingはcollapsing,surgingと比べて沿岸域への輸送エネルギーが大きいことが分かった.また,fission型の砕波発生時には,下層にある貧酸素水塊などの有害な物質がトラップされたコアによって沿岸域の浅い位置まで輸送されることが分かった.

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, 2017, Proceeding of Annual Conference, 30, 94 - 94, Japanese

  • 表面波・内部波共存場における孤立波解

    山下啓, 柿沼太郎, NAKAYAMA KEISUKE

    Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_13 - I_18, Japanese

    [Refereed]

    Scientific journal

  • 渦度を考慮した強非線形強分散波動方程式による解析

    NAKAYAMA KEISUKE, 柿沼太郎

    Nov. 2016, 土木学会論文集B2(海岸工学), Japanese

    [Refereed]

    Scientific journal

  • ソリトン波群の共鳴を対象とした強非線形強分散波動方程式による解析

    NAKAYAMA KEISUKE, 清水健司, 柿沼太郎, 辻英一

    Nov. 2016, 土木学会論文集B2(海岸工学), 72 (2), I_7 - I_12, Japanese

    [Refereed]

    Scientific journal

  • 表面孤立波及び内部孤立波の特性

    山下啓, 柿沼太郎, NAKAYAMA KEISUKE

    Jul. 2016, 土木学会論文集, 72 (1), 27 - 41, Japanese

    [Refereed]

    Scientific journal

  • 阿寒湖チュウルイ湾におけるマリモに回転運動を与える風波の将来予測に向けて

    佐野史弥, NAKAYAMA KEISUKE, 山田俊郎, 佐藤之信, 丸谷靖幸, 駒井克昭, 尾山洋一, 若菜勇

    Jun. 2016, 土木学会論文集B3(海洋開発), 72 (2), I_1021 - I_1026, Japanese

    [Refereed]

    Scientific journal

  • Roberts Bank tidal flatにおけるbiofilm形成に重要な物理・塩分環境の要因解析

    NAKAYAMA KEISUKE, 駒井克昭, Robert W. Elner, 桑江朝比呂

    Jun. 2016, 土木学会論文集B3(海洋開発), 72 (2), I_1099 - I_1104, Japanese

    [Refereed]

    Scientific journal

  • Suspended sediment transport estimation by X-ray fluorescence analysis

    C. Beitia, NAKAYAMA KEISUKE, Y. Maruya, N. Ohtsu, S. Yamasaki, M. Yamane, A. Wyatt, K. Komai

    Mar. 2016, Annual Journal of Hydraulic Engineering, JSCE, 72 (4), I_1039 - I_1044, English

    [Refereed]

    Scientific journal

  • TAKEUCHI Tomohiko, KOMAI Katsuaki, NAKAYAMA Keisuke, WATANABE Kenta, ICHIMI Kazuhiko, YAMADA Toshiro, KUWAE Tomohiro

     Dissolved organic matter was measured by using Fluorescence Spectroscopy (FS) along with salinity from snowmelt season to summer at a tidal flat in Lake Komuke at the northeast of Hokkaido. Seasonalities of dissolved nitrogen and phosphorus concentrations were also examined to clarify the dynamics of nitrogen and phosphorus in sediment-water interfaces. Salinity decreases during the snowmelt season, and FS revealed that fulvic acid-like and humic acid-like fluorescence intensities were higher in sediment pore water than in surface water especially in tidepool due to accumulation of organic matter production. It is likely that NH4-N and PO4-P concentrations in surface sediment were mainly affected by redox condition change triggered by tidal action and infiltration flow in shore side.

    Japan Society of Civil Engineers, 2016, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 72 (4), I_661 - I_666, Japanese

    [Refereed]

    Scientific journal

  • TADA Kazufumi, NAKAYAMA Keisuke, TOKORO Tatsuki, WATANABE Kenta, KUWAE Tomohiro

     In Lake Komuke, which is an important lagoon as carbon sinks, we analyzed previous data and found that salinity and biological metabolism (e.g., photosynthesis and respiration as shown by ΔDIC) are the two key environmental factors affecting CO2 fugacity in the water column. Further, the data were analyzed using an approximate expression and the numerical computations using three-dimensional numerical model during spring flood to predict spatial and temporal variation of air-sea CO2 flux. Results show that air-sea CO2 flux changes into negative (i.e., absorption) when the lake is autotrophic with ΔDIC being < -100μmol/kg.

    Japan Society of Civil Engineers, 2016, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 72 (2), I_982 - I_987, Japanese

    [Refereed]

    Scientific journal

  • Nakayama, K., Nguyen, D.H., Shintani, T., Komai, K.

    Field observations of the currents at a bending channel in the Abashiri River in Hokkaido, Japan have revealed an unexpected secondary circulation during flood tide with near-bed and near-surface currents toward the outer and inner banks of the bend, respectively. The direction of these cross-stream currents was reversed at the end of flood tide. The occurrence and shutdown of these observed unexpected secondary circulation were further investigated through the shape of the along-channel velocity profile by using a theoretical solution based on the steady-state momentum equation and the Stokes's second problem for oscillating flow. Also, an advanced numerical model was used to quantify the unexpected secondary flow. It was shown from the theoretical analysis that vertical advection plays a great role in the momentum balance affecting the direction of secondary flows. The typical secondary flow was found to occur throughout ebb tide with a pronounced near-surface maximum velocity profile. Whereas, during flood tide, the longitudinal velocity profile was characterized by a near-bed and mid-depth maximum, resulting an upwelling flow near the outer bank. These findings were reconfirmed by numerical simulations that were conducted for the entire estuary.

    WORLD SCIENTIFIC PUBL CO PTE LTD, 2016, Coastal Engineering Journal, 58 (2), 1650002, English

    [Refereed]

    Scientific journal

  • TADA Kazufumi, NAKAYAMA Keisuke, TOKORO Tatsuki, WATANABE Kenta, KUWAE Tomohiro

     The awareness of coastal blue carbon is increasing, and the dynamics of the CO2 fugacity (fCO2) in shallow coastal waters are becoming critical for evaluation of CO2 fluxes. We carried out numerical computations using a three-dimensional environmental flow model including snowmelt-related groundwater discharge and estimated fCO2 in water from salinity, biological metabolism, and calcification. Under the influence of the low salinity from the growndwater, fCO2 in water was found to increase slightly as a result of the opposite effect of a decrease in fCO2 with decreasing DIC and an increase in fCO2 with decreasing TA.

    Japan Society of Civil Engineers, 2016, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 72 (2), I_1363 - I_1368, Japanese

    [Refereed]

    Scientific journal

  • 超大型浮体構造物が有する津波高さ低減効果の数値解析

    中平達也, 柿沼太郎, 勘場隆嗣, 村上桂広, NAKAYAMA KEISUKE, 栁雄大, 山下啓

    Nov. 2015, 土木学会論文集B2(海岸工学), 71 (2), I_1033 - I_1038, Japanese

    [Refereed]

    Scientific journal

  • 河川津波を対象とした強非線形強分散波動方程式によるソリトン波の解析

    NAKAYAMA KEISUKE

    Nov. 2015, 土木学会論文集B2(海岸工学), 71 (2), I_1 - I_6, Japanese

    [Refereed]

    Scientific journal

  • マリモ球状体に回転運動を引き起こす阿寒湖チュウルイ湾の風波特性

    NAKAYAMA KEISUKE, 伊藤権吾, 若菜勇, 北村武文, 佐藤之信, 駒井克昭, 竹内友彦

    Jun. 2015, 土木学会論文集B3(海洋開発), 71 (2), I_913 - I_918, Japanese

    [Refereed]

    Scientific journal

  • オホーツク海における流氷移動ベクトル推定手法に関する検討

    佐野史弥, NAKAYAMA KEISUKE, 舘山一孝, 佐藤之信, 駒井克昭

    Jun. 2015, 土木学会論文集B3(海洋開発), 71 (2), I_217 - I_222, Japanese

    [Refereed]

    Scientific journal

  • オホーツク海における流氷と波浪・風速の関係について

    佐藤之信, NAKAYAMA KEISUKE, 舘山一孝, 佐野史弥, 駒井克昭

    Jun. 2015, 土木学会論文集B3(海洋開発), 71 (2), I_211 - I_216, Japanese

    [Refereed]

    Scientific journal

  • 生物の細胞組織構造を模した流体シミュレーターの設計と検証

    新谷哲也, NAKAYAMA KEISUKE

    Mar. 2015, 土木学会論文集B1(水工学), 71 (4), I_283 - I_288, Japanese

    [Refereed]

    Scientific journal

  • 強非線形強分散3層モデルを用いた成層湖応答解析

    NAKAYAMA KEISUKE, 吉江祐人, 新谷哲也, 柿沼太郎, H. D. Nguyen, 佐藤之信, 駒井克昭

    Mar. 2015, 土木学会論文集B1(水工学), 71 (4), I_793 - I_798, Japanese

    [Refereed]

    Scientific journal

  • New analytical form of salt intrusion model in funnel shaped estuaries: application to the Abashiri River

    H. D. Nguyen, NAKAYAMA KEISUKE, T. Shintani, K. Komai

    Mar. 2015, Journal of JSCE, 71 (4), I_19 - I_24, English

    [Refereed]

    Scientific journal

  • Nakayama, K., Maruya, Y., Matsumoto, K., Komata, M., Komai, K., Kuwae, T.

    Total nitrogen (TN), which consists of total particulate nitrogen (TPN) and total dissolved nitrogen (TDN), is transported with not only in river channels but also across the entire river basin, including via ground water and migratory animals. In general, TPN export from an entire river basin to the ocean is larger than TDN in a mountainous region. Since marine derived nutrients (MDN) are hypothesized to be mainly transported as suspended matters from the ground surface, it is necessary to investigate the contribution of MDN to the forest floor (soils) in order to quantify the true role of MDN at the river ecosystem scale. This study investigated TN export from an entire river basin, and also we estimated the contribution of pink (Oncorhynchus gorbuscha) and chum salmon (O. keta) to total oceanic nitrogen input across a river basin. The maximum potential contribution of TN entering the river basin by salmon was found to be 23.8 % relative to the total amount of TN exported from the river basin. The contribution of particulate nitrogen based on suspended sediment from the ocean to the river basin soils was 22.9 % with SD of 3.6 % by using stable isotope analysis (SIA) of nitrogen (δ15N).

    Copernicus GmbH, 2015, Biogeosciences Discussions, 12 (21), 18185 - 18211, English

    [Refereed]

    Scientific journal

  • TAKEUCHI Tomohiko, KOMAI Katsuaki, NAKAYAMA Keisuke, WATANABE Kenta, ICHIMI Kazuhiko, SATO Yukinobu, KUWAE Tomohiro

     In Lake Komuke, located in the northeast of Hokkaido, salinity and water level, and groundwater level of the vicinity of tidal flats were observed in the tidal flat in the snowmelt season to summer, and numerical analysis of the infiltration flow accompanied by snowmelt. In field observation results, water level in terrestrial groundwater level and tidal flats, landward groundwater level was higher in the snowmelt season than the other season. From further results of numerical analysis, the salinity in tidal flat was forced not to increase widely in the case of high landward groundwater level than in the case of low landward groundwater level. Moreover, up-welling was slightly strong in the case of high groundwater level, and made sediment salinity lower. The aquatic organisms can live in low salinity zone kept in the tidal flat in the spring season. It is the evidence that the many birds feeding these aquatic organisms in the spring season are frequently observed.

    Japan Society of Civil Engineers, 2015, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 71 (2), I_856 - I_861, Japanese

    [Refereed]

    Scientific journal

  • T. Okada, Y. Maruya, K. Nakayama, E. Iseri

    The eelgrass in Miyako Bay was greatly damaged by the tsunami. For future restoration of the eelgrass, we collected sediments from 110 stations in the bay and analyzed particle-size distribution and chemical composition in 2012 and 2013. The distribution of eelgrass was also measured at the same stations. The sediments on the south and west coast were suitable for eelgrass. On the other hand, the sediments on the east coast were coarser. The chemical composition indicated that we could not expect the supply of sand from the main river to the east coast. We estimated that the restoration of eelgrass on the east coast would be slower than on the west and south coast.

    Japan Society of Civil Engineers, Nov. 2014, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 70 (2), 1186 - 1190, Japanese

    [Refereed]

    Scientific journal

  • 宮古湾における津波被害からのアマモ場の復元の可能性について

    岡田知也, 丸谷靖幸, NAKAYAMA KEISUKE

    Nov. 2014, 土木学会論文集B2(海岸工学), 70 (2), I_1186 - I_1190, Japanese

    [Refereed]

    Scientific journal

  • 渦度を考慮した強非線形強分散波動方程式により再現されたソリトン波の解析

    吉江祐人, NAKAYAMA KEISUKE

    Nov. 2014, 土木学会論文集B2(海岸工学), 70 (2), I_1 - I_5, Japanese

    [Refereed]

    Scientific journal

  • Identification of the dominant suspended sediment sources in a river basin by using X-ray fluorescence analysis as a fingerprint-type method

    C. Beitia, NAKAYAMA KEISUKE, N. Ohtsu, M. Yamane, S. Yamasaki, Y. Maruya, K. Komai

    Sep. 2014, Proceedings of 19th Congress of the Asia and Pacific Division of the International Association for Hydro-Environment Engineering and Research, 19, English

    [Refereed]

    International conference proceedings

  • Characteristics of river water and nutrient discharge in a wetland

    K. Komai, NAKAYAMA KEISUKE, Y. Fukuoka, M. Kawai, S. Nakashita, Y. Ichikawa

    Sep. 2014, Proceedings of 19th Congress of the Asia and Pacific Division of the International Association for Hydro-Environment Engineering and Research, 19, English

    [Refereed]

    International conference proceedings

  • Nonlinear oblique interaction of large amplitude internal solitary waves

    NAKAYAMA KEISUKE, Y. Sato, Y. Yoshie, T. Kakinuma, H. D. Nguyen, K. Komai

    Jul. 2014, Proceedings of International Conference of Coastal Engineering, 34, English

    [Refereed]

    International conference proceedings

  • 異なる斜面勾配における内部ケルビン波の砕波により誘起される流れ

    小窪一毅, NAKAYAMA KEISUKE, 新谷哲也, 大塚淳一, 渡部靖憲, 柿沼太郎, 駒井克昭, 清水健司

    Jun. 2014, 土木学会論文集B3(海洋開発), 70 (2), I_201 - I_206, Japanese

    [Refereed]

    Scientific journal

  • 内部ケルビン波の砕波による水平循環の発達と減衰

    小窪一毅, NAKAYAMA KEISUKE, 新谷哲也, 大塚淳一, 渡部靖憲, 柿沼太郎, 駒井克昭, 清水健司

    Mar. 2014, 土木学会論文集B1(水工学), 70 (4), I_1195 - I_1200, Japanese

    [Refereed]

    Scientific journal

  • 知床を対象としたMRI-AGCM3.1Sを用いた栄養流出量の将来予測に向けて

    丸谷靖幸, NAKAYAMA KEISUKE, 仲江川敏之, 井上徹教, 小俣雅嗣, 石田哲也, 駒井克昭

    Mar. 2014, 土木学会論文集B1(水工学), 70 (4), I_1219 - I_1224, Japanese

    [Refereed]

    Scientific journal

  • 汽水湖における有機泥の沈降速度の推定と界面特性に関する考察

    駒井克昭, 日比野忠史, 中下慎也, 戸塚優平, 伊藤立誠, 丸谷靖幸, NAKAYAMA KEISUKE

    Mar. 2014, 土木学会論文集B1(水工学), 70 (4), I_1585 - I_1590, Japanese

    [Refereed]

    Scientific journal

  • Nakayama, K., Shintani, T., Shimizu, K., Okada, T., Hinata, H., Komai, K.

    This study investigates the horizontal and residual circulations in Tokyo Bay using field observations, numerical simulations, and theoretical analysis. Numerical simulations show that the observed deepening of isopycnals and associated anticyclonic horizontal circulation in the bay head are mainly driven by negative wind stress curl. The effects of river discharge, surface heat fluxes, and tides are found to be small. Under strong wind events, the wind stress curl over the bay head can be large enough to make the surface Ekman layer strongly nonlinear. Theoretical and numerical analyses show that, under large negative wind stress curl, the nonlinearity tends to induce positive pumping velocity (at the base of the surface mixed layer) that counteracts the Ekman pumping however, the typical duration of wind events in the bay head is not long enough to induce positive pumping under negative wind stress curl. These results and historical wind data suggest that the average horizontal circulation and residual circulation immediately below the surface mixed layer in Tokyo Bay are, respectively, cyclonic and convergent in summer but anticyclonic and divergent in winter. © 2014. American Geophysical Union. All Rights Reserved.

    Blackwell Publishing Ltd, 2014, Journal of Geophysical Research: Oceans, 119 (3), 1977 - 1992, English

    [Refereed]

    Scientific journal

  • YOSHIE Yuto, MARUYA Yasuyuki, NAKAYAMA Keisuke, KOMAI Katsuaki, SHINTANI Tetsuya, WATANABE Kenta, ICHIMI Kazuhiko, KUWAE Tomohiro

     In Lake Komuke, which is one of the most significant lakes for immigration birds, we carried out field experiments of flow field and water quality. Lake Komuke consists of a main lake and the other two small lakes. The main lake is found to have higher salinity compared to the other two small lakes. During the snow melt period, the small lakes are found to have less salinity compared to summer, which is confirmed by the numerical computations using three-dimensional numerical model. As a result, tidal flats in the small lakes have larger residual time of sea water which is significant for immigration birds.

    Japan Society of Civil Engineers, 2014, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 70 (2), I_1176 - I_1181, Japanese

    [Refereed]

    Scientific journal

  • KOMAI Katsuaki, NAKAYAMA Keisuke, MATSUBARA Kenya, KAWAGUCHI Takayuki, YAMASAKI Shintaro, WATANABE Kenta, ICHIMI Kazuhiko, KUWAE Tomohiro

     In Lake Komuke, an important flyway in Japan, salinity, water level, and seepage flow were observed in tidal flats and seasonal variation of dissolved organic matters were identified by fluorescence spectroscopy in order to clarify the relationship between water qualities and groundwater flow during spring and summer. At the offshore of the sandbar, the seasonality of fluorescence intensity of fulvic acid-like substances derived from soil in large lake means the seasonal variation of influence of river water and groundwater on water quality in the tidal flat. Groundwater in the tidal flat flew upward by an order of magnitude larger in spring than in summer. From the results of surface water in the tidal flat and the profiles of groundwater, upward flow likely reduces the increase of salinity in the groundwater.

    Japan Society of Civil Engineers, 2014, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 70 (2), I_1182 - I_1187, Japanese

    [Refereed]

    Scientific journal

  • Adaptive management in Kushiro Wetland in the context of salt wedge intrusion due to sea level rise

    A. Nakamoto, NAKAYAMA KEISUKE, T. Shintani, Y. Maruya, K. Komai, T. Ishida, Y. Makiguchi

    Dec. 2013, Hydrological Research Letters, 7 (1), 1 - 5, English

    [Refereed]

    Scientific journal

  • 内部ケルビン波の砕波による水平循環の発生機構解明

    小窪一毅, NAKAYAMA KEISUKE, 新谷哲也, 柿沼太郎, 大塚淳一, 渡部靖憲, 駒井克昭, Kenji Shimizu

    Nov. 2013, 土木学会論文集B2(海岸工学), 69 (2), I_451 - I_455, Japanese

    [Refereed]

    Scientific journal

  • 河川津波の進行・発達と河道内における変形に関する解析

    佐藤之信, 吉江祐人, NAKAYAMA KEISUKE, 柿沼太郎, 駒井克昭

    Nov. 2013, 土木学会論文集B2(海岸工学), 69 (2), I_161 - I_165, Japanese

    [Refereed]

    Scientific journal

  • 網走川河口における塩水遡上への吹送流の影響評価

    佐藤之信, NAKAYAMA KEISUKE, 新谷哲也, 駒井克昭

    Jun. 2013, 土木学会論文集B3(海洋開発), 69 (2), I_1195 - I_1200, Japanese

    [Refereed]

    Scientific journal

  • 東京湾スケールにおけるメッシュアスペクト比と非静水圧効果の解析

    NAKAYAMA KEISUKE, 新谷哲也, 清水健司, 木下直貴, 岡田知也, 佐藤之信, 丸谷靖幸, 駒井克昭

    Jun. 2013, 土木学会論文集B3(海洋開発), 69 (2), I_709 - I_714, Japanese

    [Refereed]

    Scientific journal

  • Suspended sediment transport in a river basin by using X-ray fluorescence analysis

    K. Kokubo, NAKAYAMA KEISUKE, T. Shintani, T. Ishida, Y. Maruya, K. Komai

    Jun. 2013, Asia Pacific Association of Hydrology and Water Resources (APHW 2013), 18, English

    [Refereed]

    International conference proceedings

  • Hydroclimate projections for Panama in the late 21st Century

    J. Fábrega, T. Nakaegawa, R. Pinzón, NAKAYAMA KEISUKE

    May 2013, Hydrological Research Letters, 7 (2), 23 - 29, English

    [Refereed]

    Scientific journal

  • 網走川河口域で発生する塩水遡上に関する数値的検討

    新谷哲也, 中山恵介

    Mar. 2013, 土木学会論文集B1(水工学), 69 (4), I_829 - I_834, Japanese

    [Refereed]

    Scientific journal

  • 網走湖におけるメタン発生メカニズムの解明

    丸谷靖幸, 中山恵介, 佐々木正史, 新谷哲也, 駒井克昭, 岡田知也, 菅原庸平, 崇田徳彦

    Mar. 2013, 土木学会論文集B1(水工学), 69 (4), I_1435 - I_1440, Japanese

    [Refereed]

    Scientific journal

  • Dutta, D., Wright, W., Nakayama, K., Sugawara, Y.

    2013, Natural Hazards Review, 14 (1), 52 - 65, English

    [Refereed]

    Scientific journal

  • Nakayama, K., Maruya, Y., Nakaegawa, T., Komai, K., Kokubo, K., Ishida, T., Okada, T.

    2013, Hydrological Processes, 27 (23), 3280 - 3291, English

    [Refereed]

    Scientific journal

  • INTERACTION OF SURFACE AND INTERNAL WAVES WITH VERY LARGE FLOATING STRUCTURES

    Taro Kakinuma, Kei Yamashita, Keisuke Nakayama

    Interaction of surface/internal water waves with a floating platform is discussed with nonlinearity of fluid motion and flexibility of oscillating structure. The set of governing equations based on a variational principle is applied to a one- or two-layer fluid interacting with a horizontally very large and elastic floating thin-plate. Calculation results of surface displacements are compared with the existing experimental data, where a tsunami, in terms of a solitary wave, propagates across one-layer water with a floating thin-plate. We also simulate surface and internal waves due to a point load, such as an airplane, moving on a very large floating structure in shallow water. The wave height of the surface or internal mode is amplified when the moving velocity of point load is equal to the surface or internal wave celerity, respectively.

    WORLD SCIENTIFIC PUBL CO PTE LTD, 2013, COASTAL STRUCTURES 2011, VOL 1 & 2, 1, 913 - 922, English

    [Refereed]

    International conference proceedings

  • MARUYA Yasuyuki, NAKAYAMA Keisuke, KOMAI Katsuaki, WATANABE Kenta, MIYOSHI Eiichi, ICHIMI Kazuhiko, KUWAE Tomohiro

     Lake Komuke is a typical brackish lake, which is located in the northeastern part of Hokkaido. A lot of birds, such as sipes and plovers, are well known to migrate in Lake Komuke. It is thus important to understand ecological system in Lake Komuke in order to conserve such a significant nature. Mass transport and water quality are the key factors which control ecosystem in an enclosed water body. Therefore, this study aims to clarify the characteristics of water quality and flow field. Conceptual water exchange model was applied and it is revealed that oceanic water intrudes into the lake and the change in surface water level is smaller than the tidal amplitude, which may enhance the primary production of phytoplankton in Lake Komuke.

    Japan Society of Civil Engineers, 2013, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 69 (2), I_1228 - I_1233, Japanese

    [Refereed]

    Scientific journal

  • マッハステム形成過程の数値解析

    山下啓, 柿沼太郎, 山元公, 中山恵介

    Nov. 2012, 土木学会論文集B2(海岸工学), 68 (2), I_6 - I_10, Japanese

    [Refereed]

    Scientific journal

  • 振幅の違いを考慮したソリトン共鳴による大振幅ソリトンの解析

    中山恵介, 柿沼太郎, 辻英一, 及川正行

    Nov. 2012, 土木学会論文集B2(海岸工学), 68 (2), I_1 - I_5, Japanese

    [Refereed]

    Scientific journal

  • Shoaling of nonlinear internal waves on a uniformly sloping beach

    Yamashita K, T. Kakinuma, K. Nakayama

    Jul. 2012, Proceedings of International Conference of Coastal Engineering, 33, 1264, English

    [Refereed]

    International conference proceedings

  • Nonlinear oblique interaction of large amplitude internal solitary waves

    Nakayama K, T. Kakinuma, H. Tsuji, M. Oikawa

    Jul. 2012, Proceedings of International Conference of Coastal Engineering, 33, 1053, English

    [Refereed]

    Scientific journal

  • 風と塩水遡上の関連性に関する統計解析

    早川博, 加藤淳子, 中山恵介, 崇田徳彦, 中内勲, 石田哲也

    Jul. 2012, 土木学会論文集B3(海洋開発), 68 (2), I_745 - I_750, Japanese

    [Refereed]

    Scientific journal

  • 東京湾を対象としたPartial Cell の適用性の検討

    丸谷靖幸, 吉江祐人, 中山恵介, 新谷哲也, 木下直貴, 駒井克昭, 小窪一毅, 加藤淳子

    Jul. 2012, 土木学会論文集B3(海洋開発), 68 (2), I_997 - I_1002, Japanese

    [Refereed]

    Scientific journal

  • 河口域における水位変化に伴う浸透流の変動機構

    駒井克昭, 川西澄, Mahdi Razaz, 小窪一毅, 渡辺聡, 中山恵介, Peter Nielsen

    Jul. 2012, 土木学会論文集B2(海岸工学), 68 (2), I_1096 - I_1100, Japanese

    [Refereed]

    Scientific journal

  • 内部ケルビン波の砕波により誘起される流れ

    中山恵介, 小窪一毅, 新谷哲也, 大塚淳一, 丸谷靖幸, 渡部靖憲, 駒井克昭, 岡田知也

    Jul. 2012, 土木学会論文集B2(海岸工学), 68 (2), I_926 - I_930, Japanese

    [Refereed]

    Scientific journal

  • 環境流体解析のための簡易Wetting and Dryingスキーム

    新谷哲也, 中山恵介, 中本篤嗣

    Mar. 2012, 土木学会論文集B1(水工学), 68 (4), I_1249 - I_1254, Japanese

    [Refereed]

    Scientific journal

  • 元素分析による細粒土砂輸送割合の推定方法開発

    石田哲也, 早川博, 中山恵介, 岡田知也, 丸谷靖幸, 駒井克昭, 堀田伸之, 藤井博司, 加藤淳子

    Mar. 2012, 土木学会論文集B1(水工学), 68 (4), I_637 - I_642, Japanese

    [Refereed]

    Scientific journal

  • 知床を対象とした海陸の栄養塩循環機構の解明

    Aynur Abliz, 中山恵介, 丸谷靖幸, 井上徹教, 桑江朝比呂, 舘山一孝, 岡田知也, 加藤淳子, 石田哲也

    Mar. 2012, 土木学会論文集B1(水工学), 68 (4), I_721 - I_726, Japanese

    [Refereed]

    Scientific journal

  • Increase in simple precipitation intensity index in Panama

    K. Nakayama, C. Beitia, E. Vallester, R. Pinzon, J. Fabrega, T. Nakaegawa, Y. Maruya, J. Espinosa, B. Olmedo, J. Kato, K. Komai

    Mar. 2012, Annual Journal of Hydraulic Engineering, JSCE, 68 (4), I_163 - I_168, Japanese

    [Refereed]

    Scientific journal

  • INFLUENCE OF VELOCITY DISTRIBUTION AND DENSITY STRATIFICATION ON GENERATION OR PROPAGATION OF TSUNAMIS

    Taro Kakinuma, Kei Yamashita, Keisuke Nakayama

    A set of wave equations derived on the basis of a variational principle in consideration of both strong nonlinearity and strong dispersion of surface/internal waves is numerically solved to simulate generation and propagation of tsunamis in the vertical two-dimension. The velocity potential in each fluid layer is expanded into a power series of vertical position, such that the accuracy of vertical distribution of velocity depends on the number of expansion terms. Numerical results of surface displacement are compared with the existing experimental data, where tsunamis are generated by the seabed uplift. When the fundamental equations are reduced to nonlinear shallow water equations, the numerical model cannot represent propagation of a long wave group especially in distant-tsunami propagation, leading to overestimation of both the wave height and wave steepness of the first wave. The wave height becomes larger in the stratified ocean than that in a one-layer case, although the present density distribution hardly affects the tsunami phase over a long-distance travel.

    WORLD SCIENTIFIC PUBL CO PTE LTD, 2012, ADVANCES IN GEOSCIENCES VOL 28: ATMOSPHERIC SCIENCE (AS) & OCEAN SCIENCE (OS), 67 - 78, English

    [Refereed]

    International conference proceedings

  • Nutrient circulation due to the interaction between terrestrial and oceanic systems

    K. Nakayama, T. Kuwae, Y. Maruya, A. Abliz, T. Inoue, K. Tateyama

    the 50th ECSA conference, 2012, The 50th Estuaries and Coastal Areas conference, O7.22, English

    [Refereed]

  • Estimation of salt wedge intrusion in Kushiro wetland due to sea level rise

    A. Nakamoto, K, Nakayama,T. Shintani, Y. Maruya, T. Ishida, K. Houmura, Y. Makiguchi

    18th Congress of the Asia and Pacific Division of the International Association for Hydro-Environment Engineering and Research, 2012, Proceedings of 18th Congress of the Asia and Pacific Division of the International Association for Hydro-Environment Engineering and Research, 159 - 160, English

    [Refereed]

  • INFLUENCE OF VELOCITY DISTRIBUTION AND DENSITY STRATIFICATION ON GENERATION OR PROPAGATION OF TSUNAMIS

    T. Kakinuma, K. Nakamura, K. Yamashita, K. Nakayama

    A set of wave equations derived on the basis of a variational principle in consideration of both strong nonlinearity and strong dispersion of surface/internal waves is numerically solved to simulate generation and propagation of tsunamis in the vertical two-dimension. The velocity potential in each fluid layer is expanded into a power series of vertical position, such that the accuracy of vertical distribution of velocity depends on the number of expansion terms. Numerical results of surface displacement are compared with the existing experimental data, where tsunamis are generated by the seabed uplift. When the fundamental equations are reduced to nonlinear shallow water equations, the numerical model cannot represent propagation of a long wave group especially in distant-tsunami propagation, leading to overestimation of both the wave height and wave steepness of the first wave. The wave height becomes larger in the stratified ocean than that in a one-layer case, although the present density distribution hardly affects the tsunami phase over a long-distance travel.

    WORLD SCIENTIFIC PUBL CO PTE LTD, 2012, PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON APAC 2011, 28, 67 - 78, English

    [Refereed]

    International conference proceedings

  • Taro Kakinuma, Kei Yamashita, Keisuke Nakayama

    Interaction of surface/internal water waves with a floating platform is discussed with nonlinearity of fluid motion and flexibility of oscillating structure. The set of governing equations based on a variational principle is applied to a one- or two-layer fluid interacting with a horizontally very large and elastic thin plate floating on the water surface. Calculation results of surface displacements are compared with the existing experimental data, where a tsunami, in terms of a solitary wave, propagates across one- layer water with a floating thin plate. We also simulate surface and internal waves due to a point load, such as an airplane, moving on a very large floating structure in shallow water. The wave height of the surface or internal mode is amplified when the velocity of moving point load is equal to the surface- or internal-mode celerity, respectively.

    HINDAWI PUBLISHING CORPORATION, 2012, JOURNAL OF APPLIED MATHEMATICS, 2012, 1 - 14, English

    [Refereed]

    Scientific journal

  • Keisuke Nakayama, Tetsuya Shintani, Kazuki Kokubo, Taro Kakinuma, Yasuyuki Maruya, Katsuaki Komai, Tomonari Okada

    Residual currents due to internal wave breaking on a uniform slope were investigated in a two-layer system using laboratory experiments and numerical computations for different layer configurations. Internal wave-induced currents over a slope were measured in an experimental tank using PIV and also reproduced by a hydrodynamic model to quantify the detailed velocity field. The present results reveal that the critical level derived from the KdV theorem is a useful parameter for classifying the dynamics of internal waves breaking over a slope. As the horizontal distance from the critical level point to the internal wave breaking point increases, internal waves break more dynamically over the slope. Consequently, residual currents are enhanced near the breaking point. These findings increase our capacity to understand flux paths of biological and chemical substances in the stratified coastal ocean. © 2012. American Geophysical Union. All Rights Reserved.

    Blackwell Publishing Ltd, 2012, Journal of Geophysical Research: Oceans, 117 (10), 1 - 11, English

    [Refereed]

    Scientific journal

  • Sato, C., Nakayama, K., Furukawa, K.

    2012, Estuarine, Coastal and Shelf Science, 109, 91 - 97, English

    [Refereed]

    Scientific journal

  • INFLUENCE OF VELOCITY DISTRIBUTION AND DENSITY STRATIFICATION ON GENERATION OR PROPAGATION OF TSUNAMIS

    T. Kakinuma, K. Nakamura, K. Yamashita, K. Nakayama

    A set of wave equations derived on the basis of a variational principle in consideration of both strong nonlinearity and strong dispersion of surface/internal waves is numerically solved to simulate generation and propagation of tsunamis in the vertical two-dimension. The velocity potential in each fluid layer is expanded into a power series of vertical position, such that the accuracy of vertical distribution of velocity depends on the number of expansion terms. Numerical results of surface displacement are compared with the existing experimental data, where tsunamis are generated by the seabed uplift. When the fundamental equations are reduced to nonlinear shallow water equations, the numerical model cannot represent propagation of a long wave group especially in distant-tsunami propagation, leading to overestimation of both the wave height and wave steepness of the first wave. The wave height becomes larger in the stratified ocean than that in a one-layer case, although the present density distribution hardly affects the tsunami phase over a long-distance travel.

    WORLD SCIENTIFIC PUBL CO PTE LTD, 2012, PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON APAC 2011, 6, TSS_07, English

    [Refereed]

    International conference proceedings

  • LARGE AMPLITUDE SOLITARY WAVES DUE TO SOLITARY RESONANCE

    K. Nakayama, T. Kakinuma, H. Tsuji, M. Oikawa

    A fully-nonlinear and strongly-dispersive internal wave equation model was used to investigate the interaction between internal solitary waves in a two-dimensional plane in order to clarify the resonance of fully-nonlinear internal solitary waves, which is one of the reasons for the occurrence of large amplitude solitary waves (LASW). The 3rd order theoretical solutions for internal waves in a two-layer system was used as initial conditions and a "stem" was confirmed to occur when the incident wave angle was less than certain critical angle. This study revealed the occurrence of LASW by using a fully-nonlinear and strongly-dispersive internal wave equation model.

    WORLD SCIENTIFIC PUBL CO PTE LTD, 2012, PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON APAC 2011, 6, WME_09, English

    [Refereed]

    International conference proceedings

  • Influence of freshwater input and bay reclamation on long-term changes in seawater residence times in Tokyo Bay, Japan

    T. Okada, NAKAYAMA KEISUKE, T. Takao, K. Furukawa

    Dec. 2011, Hydrological Processes, 24, 2694 - 2702, English

    [Refereed]

    Scientific journal

  • NAKAYAMA KEISUKE, A. Aynur, T. Nakaegawa, Y. Maruya

    This study aims to evaluate nutrient flux to the coast from the inland areas of Shiretoko in order to understand the key factors controlling the ecological systems of the coast. As an external force, rainfall is considered one of the most significant components controlling nutrient supply to coastal systems in this area. Therefore, to estimate nutrient supply in the future, the bias correction was applied by using Meteorological Research Institute Global Climate Model, which shows good agreement with Automated Meteorological Data Acquisition System data. A synthetic generation technique is used to produce hourly rainfall data, which is necessary for evaluating nutrient supply in Shiretoko. The robustness of the duplicated hourly rainfall intensity was investigated, which reveals that its standard deviation controls nutrient flux when nonlinearity becomes stronger for the evaluation of nutrient supply from a river basin.

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, Dec. 2011, Hydrological Research Letters, 5, 47 - 51, English

    [Refereed]

    Scientific journal

  • 東京湾における貧酸素水塊の解消要因である強風の将来予測に向けて

    丸谷靖幸, アイヌルアブリズ, 中山恵介, 仲江川敏之, 古川恵太, 駒井克明, 目淑範

    Nov. 2011, 土木学会論文集B2(海岸工学), 67 (2), I_921 - I_925, Japanese

    [Refereed]

    Scientific journal

  • ソリトン共鳴により発生する大振幅ソリトンの解析

    中山恵介, 柿沼太郎, 辻英一, 及川正行

    Nov. 2011, 土木学会論文集B2(海岸工学), 67 (2), I_6 - I_10, Japanese

    [Refereed]

    Scientific journal

  • 薄板状浮体構造物上を移動する荷重により生成される表面波及び内部波の数値解析

    山下啓, 柿沼太郎, 中山恵介

    Jul. 2011, 土木学会論文集B3(海洋開発), 67 (2), I_109 - I_114, Japanese

    [Refereed]

    Scientific journal

  • 東京湾の水環境予測を目指したGCM データの利用

    Aynur Abliz, 丸谷靖幸, 中山恵介, 仲江川敏之, 古川恵太

    Jul. 2011, 土木学会論文集B3(海洋開発), 67 (2), I_277 - I_282, Japanese

    [Refereed]

    Scientific journal

  • 津波の生成や伝播に対する流速分布及び密度成層の影響

    柿沼太郎, 山下啓, 帖佐繁明, 藤間功司, 中山恵介

    Jul. 2011, 土木学会論文集B3(海洋開発), 67 (2), I_511 - I_516, Japanese

    [Refereed]

    Scientific journal

  • ANALYSIS OF MECHANISM OF WATER CIRCULATION IN KUSHIRO WETLAND FROM COMPARISONS WITH 1970S

    Y. Maruya, Y. Sugawara, A. Abliz, T. Ishida, K. Nakayama

    Japan Society of Civil Engineers, Mar. 2011, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 67 (4), 547 - 552, Japanese

    [Refereed]

    Scientific journal

  • 降雨のインパクトによる高濁度水発生と細粒土砂輸送に関する現地観測とモデル化

    石田哲也, 中山恵介, 丸谷靖幸, 大森未音, 菅原庸平, Aynur Abliz, 上野義勝

    Mar. 2011, 土木学会論文集B1(水工学), 67 (4), I_1315 - I_1320, Japanese

    [Refereed]

    Scientific journal

  • 1970年代と比較した釧路湿原における水循環機構解析

    丸谷靖幸, 菅原庸平, Aynur Abliz, 石田哲也, 中山恵介

    Mar. 2011, 土木学会論文集B1(水工学), 67 (4), I_547 - I_552, Japanese

    [Refereed]

    Scientific journal

  • 海面上昇を考慮した釧路湿原への塩水遡上の影響評価

    中本篤嗣, 新谷哲也, 中山恵介, 丸谷靖幸, 石田哲也, 法村賢一

    Mar. 2011, 土木学会論文集B1(水工学), 67 (4), I_1351 - I_1356, Japanese

    [Refereed]

    Scientific journal

  • 安定同位体比による知床ラウス川を通じた海起源栄養塩の流域内分布

    Aynur Abliz, 中山恵介, 丸谷靖幸, 桑江朝比呂, 岡田知也, 石田哲也

    Mar. 2011, 土木学会論文集B1(水工学), 67 (4), I_1303 - I_1308, Japanese

    [Refereed]

    Scientific journal

  • M. Arthur Simanjuntak, Joerg Imberger, Keisuke Nakayama, Tadaharu Ishikawa

    Tone River is a shallow, tidal estuary with a controllable upstream freshwater discharge via a barrage. The mixing characteristics in the benthic and interfacial regions of the Tone River estuary were investigated during a time window of maximum freshwater discharge and high shear, using temperature and velocity microstructure measurements. Although the production of turbulent kinetic energy from mean shear was high throughout the water column, the intermittency of both up- and down-gradient buoyancy fluxes resulted in negligible net down-gradient mixing. These opposing fluxes were incorporated into a turbulent closure scheme by using the concept of percentage down-gradient flux. A comparison of vertical diffusivity from two alternative closures suggests that the stratification imposed a length scale limitation on the vertical turbulent excursions that proved crucial for the transition region between the benthic and interfacial regions; it is argued that a Richardson-number based closure is both conceptually and practically adequate to represent the effect of length-scale limitation and percentage down-gradient flux.

    TAYLOR & FRANCIS LTD, 2011, JOURNAL OF HYDRAULIC RESEARCH, 49 (6), 791 - 798, English

    [Refereed]

    Scientific journal

  • T. Ishida, NAKAYAMA KEISUKE, T. Okada, Y. Maruya, K. Onishi, M. Omori

    Production and transportation of suspended sediment was investigated by sampling surface soils in 18 domains over an entire river basin. Particle size distributions alone suggested that all domains were a source of suspended sediment. Chemical composition analysis however showed that the transport rate of suspended sediment was more closely related to the type of surface soil than to land use. A method was developed which enables estimation of the relative suspended sediment transport rates from each domain of a river basin to its downstream end. The model's validity was verified through good agreement with field sampling results.

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, Dec. 2010, Hydrological Research Letters, 4, 55 - 59, English

    [Refereed]

    Scientific journal

  • Keisuke Nakayama, Murugesu Sivapalan, Chizuru Sato, Keita Furukawa

    This paper uses derived distribution analysis to explore the process controls of the onset of and recovery from hypoxic conditions in Tokyo Bay, Japan. A conceptual, lumped model of dissolved oxygen (DO) dynamics in Tokyo Bay is proposed and, through comparison with a three-dimensional simulation model, is verified to have sufficient accuracy for the prediction of the onset of and recovery from hypoxia. This conceptual DO model was implemented in continuous simulation mode, with 14 years of wind data and data on streamflow entering the Tokyo Bay, and was used to identify and quantify the various process controls of the onset of and recovery from hypoxia. The underlying process controls were identified to be streamflow discharge, as well as duration and strength of both northeast "positive" winds and southwest "negative" winds. The analysis helped to isolate, in particular, the potential for rapid and strong recovery from hypoxia due to "strong negative winds", (i.e., negative winds that exceed a wind speed threshold of 10 m s(-1)) and the critical roles of the duration of these strong winds and the antecedent DO concentration on the strength of DO recovery. Motivated by these results, derived distribution analysis is adopted to predict the strength of DO recovery during periods of strong winds, using a simplified model of DO recovery, focused on isolated strong winds, that explicitly captures the effects of both wind duration and antecedent DO concentration.

    AMER GEOPHYSICAL UNION, Dec. 2010, WATER RESOURCES RESEARCH, 46, 1 - 15, English

    [Refereed]

    Scientific journal

  • Residual circulation due to internal waves shoaling on a slope

    NAKAYAMA KEISUKE, J. Imberger

    Dec. 2010, Limnology and Oceanography, 55, 1009 - 1023, English

    [Refereed]

    Scientific journal

  • Internal waves in a two-layer system using fully nonlinear internal-wave equations

    NAKAYAMA KEISUKE, T. Kakinuma

    Dec. 2010, International Journal for Numerical Methods in Fluids, 62, 574 - 590, English

    [Refereed]

    Scientific journal

  • Y. Maruya, NAKAYAMA KEISUKE, T. Shintani, M. Yonemoto

    This study aims to reveal the factors most useful for evaluating the influence of wind on entrainment from the lower to upper layer in a two-layer system. Lake Abashiri, which is a typical brackish lake, is chosen as a study area because a distinct two-layer system exists due to salt-wedge intrusion from the ocean. To evaluate entrainment velocity between two layers, a 3D numerical computation is applied, showing good agreement with field observations. Computations suggest that the entrainment velocity estimated using the Richardson number is smaller than that from field observations. Thus, other factors are computed suggesting that use of the Lake number is more effective in estimating entrainment velocity due to internal wave breaking and interfacial fluctuation than use of the Effective Wedderburn number.

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, Dec. 2010, Hydrological Research Letters, 4, 70 - 74, English

    [Refereed]

    Scientific journal

  • K. Nakayama, T. Kakinuma, M. Oikawa, H. Tsuji, Y. Maruya

    Applicability of the 3rd order theoretical solutions for internal waves in a two-layer system is investigated by using a strongly nonlinear and dispersive internal wave model. The 3rd order solution is derived using the 9th order internal wave equations. The 3rd order solution is found to give larger wavelength scale compared to KdV theory. The applicability of the 3rd order solution is confirmed to be high when the amplitude of internal solitary wave is 5% of the lower layer thickness. A fully nonlinear strongly dispersive internal wave model reveals that high frequency internal waves are induced behind an internal solitary wave when the initial shape of internal solitary wave is larger than critical level.

    Japan Society of Civil Engineers, Nov. 2010, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 66 (1), 1 - 5, Japanese

    [Refereed]

    Scientific journal

  • 塩水遡上へ与えるストークスドリフトの影響評価

    中山恵介, 丸谷靖幸, 新谷哲也, 柿沼太郎, 中内勲, 米元光明

    Nov. 2010, 海岸工学論文集, 57, 326 - 330, Japanese

    [Refereed]

    Scientific journal

  • 内部ソリトン波の3次オーダ解による再現性の検討

    中山恵介, 柿沼太郎, 及川正行, 辻英一, 丸谷靖幸

    Nov. 2010, 海岸工学論文集, 57, 1 - 5, Japanese

    [Refereed]

    Scientific journal

  • 深水域や砕波点近傍における非線形内部波の挙動

    山下啓, 柿沼太郎, 中山恵介, 及川正行, 辻英一, 西川学

    Nov. 2010, 海岸工学論文集, 57, 171 - 175, Japanese

    [Refereed]

    Scientific journal

  • Influence of Stokes drift on salt wedge intrusion evaluated using fully-nonlinear and strongly dispersive wave equations

    Nakayama K, T. Shintani, T. Kakinuma, Y. Maruya, Y. Yonome, M. Yonemoto, I. Nakauchi

    Jul. 2010, Proceedings of International Conference of Coastal Engineering, 32, English

    [Refereed]

    Scientific journal

  • 釧路湿原への塩水遡上に関する調査と検討

    中山恵介, 佐久間慎雄, 新谷哲也, 中本篤嗣, 山村諭

    Jul. 2010, 海洋開発論文集, 26, 789 - 794, Japanese

    [Refereed]

    Scientific journal

  • 東京湾を対象とした内部ケルビン波の発生と砕波に関する検討

    中山恵介, 角谷和成, 新谷哲也, 清水健司, 福岡将太

    Jul. 2010, 海洋開発論文集, 26, 657 - 662, Japanese

    [Refereed]

    Scientific journal

  • 融雪期における高濁度水発生機構と細粒土砂輸送

    石田哲也, 中山恵介, 大西健史, 夏井皓盛, 大森未音, アイヌルアブリズ, 丸谷靖幸, 岡田知也

    Mar. 2010, 水工学論文集, 54, 43 - 438, Japanese

    [Refereed]

    Scientific journal

  • 網走湖における密度界面に対する風応力と河川流入の影響評価

    丸谷靖幸, 中山恵介, 堀松大志, 目淑範, 米元光明

    Mar. 2010, 水工学論文集, 54, 1393 - 1398, Japanese

    [Refereed]

    Scientific journal

  • Mass transport and nutrient circulation evaluated by stable isotope analysis and chemical decomposition,

    Y. Maruya, A. Abuliz, K. Nakayama, T. Kuwae, T. Okada, T. Ishida

    5th Conference of the APHW, 2010, 5th Conference of the APHW, 428 - 435, English

    [Refereed]

  • Influence of internal waves on interfacial level in Lake Abashiri

    K. Nakayama, Y. Maruya, T. Shintani, K. Shimizu, Y. Yonome, M. Yonemoto

    International Symposium on Ecohydraulics, 2010, International Symposium on Ecohydraulics 2010, 133 - 141, English

    [Refereed]

  • A NUMERICAL STUDY ON PROPAGATION OF NONLINEAR INTERNAL WAVES

    Taro Kakinuma, Kei Yamashita, Keisuke Nakayama

    Internal waves in a two-layer system are simulated using a set of nonlinear internal-wave equations, which was derived on the basis Of a variational principle without any assumptions concerning wave nonlinearity and dispersion In the cases where long internal waves reflect in a tank, interface displacements obtained by the proposed model with more than two vertically distributed functions of velocity potential are in harmony with those by the Boussinesq-type model. as well as the existing experimental data especially in the wave number In the intermediate-wave case, the present model shows different results from those through the Boussinesq-type model, which should not be applied to this case without enough consideration of the wave dispersion Internal waves propagating over a submerged breakwater are also simulated, where the vertical distribution of horizontal velocity below a crest is remarkably distributed when it starts disintegration after passing over the shoulder

    WORLD SCIENTIFIC PUBL CO PTE LTD, 2010, PROCEEDINGS OF THE 5TH INTERNATIONAL CONFERENCE ON ASIAN AND PACIFIC COASTS, VOL 3, 32, 208 - +, English

    [Refereed]

    International conference proceedings

  • NAKAYAMA Keisuke, MARUYA Yasuyuki, SHINTANI Tetsuya, KAKINUMA Taro, NAKAUCHI Isao, YONEMOTO Komei

    This paper describes the influence of surface waves on salt-wedge intrusion in terms of radiation stress. Radiation stress which includes Stokes drift effect may increase salt-wedge intrusion when surface waves propagate up a river. This study thus aims to reveal the effect of radiation stress on the distance of salt-wedge intrusion by fully nonlinear strongly dispersive internal wave equations and three-dimensional numerical computation model, Fantom3D. Fully nonlinear strongly dispersive internal wave model reveals the possibility that large radiation stress is induced near the river mouth and increases the distance of salt-wedge intrusion. Three-dimensional numerical model also demonstrates that there is a significant difference in the intrusion distance by taking into account radiation stress.

    Japan Society of Civil Engineers, 2010, PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 66 (1), 326 - 330, English

  • YAMASHITA Kei, KAKINUMA Taro, NAKAYAMA Keisuke, OIKAWA Masayuki, TSUJI Hidekazu, NISHIKAWA Manabu

    A set of nonlinear internal-wave equations, which have been derived on the basis of the variational principle without any assumptions concerning wave nonlinearity and dispersion, is applied to compare numerical results with experimental data of internal waves propagating in a deep-water region. Internal waves propagating over a uniformly sloping beach are also simulated. Internal progressive waves show remarkable shoaling after the interface reaches the critical level, after which the physical variables change discontinuously near the wave-breaking point. In the wave-breaking case of internal waves reflecting at a vertical wall, the vertical velocity of the particles in the vicinity of the interface is different from that of the moving interface on the wall, which means that the kinematic boundary condition on the interface is not satisfied.

    Japan Society of Civil Engineers, 2010, PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 66 (1), 26 - 30, English

  • M. A. Simanjuntak, J. Imberger, K. Nakayama

    The paper describes the effect of a stair-step representation of bottom topography, common in most numerical models, on the propagation of internal waves in a geophysical flow. An analytical solution was used to predict the effect of stair-step and piecewise linear representations of topography on the reflection and transmission of internal waves. The Estuary Lake and Coastal Model (ELCOM) was used to simulate the transmission of a train of small-amplitude internal gravity waves propagated along a variable depth rectangular channel containing a linearly stratified fluid. The effect of the different obstacle approximations was examined in terms of the interference of the resulting wave number content, and hence the associated reflection coefficients, which could be directly compared to the analytical theory. It was shown that for Gaussian obstacles of varying lengths and heights, the full bottom cells and partial bottom cells solutions from ELCOM agree with the stair-step and piecewise linear solutions from the theory, respectively. It was shown that when Gaussian obstacles with weak slopes are represented by stair steps, an aliasing that is similar to that in discrete Fourier transform can occur, resulting in reflection coefficients that are much higher than the exact solution. On the other hand, piecewise linear approximations produce significantly attenuated aliasing. An immersed boundary technique that enforces a no-flux condition at the actual sloping bottom, similar to that of the analytical solution, is found not to produce better numerical results. Copyright 2009 by the American Geophysical Union.

    Blackwell Publishing Ltd, 08 Dec. 2009, Journal of Geophysical Research: Oceans, 114 (12), English

    [Refereed]

    Scientific journal

  • Effects of spatial grid resolution on river flow and surface inundation simulation by physically based distributed modelling approach

    D. Dutta, NAKAYAMA KEISUKE

    Dec. 2009, Hydrological Processes, 23, 534 - 545, English

    [Refereed]

    Scientific journal

  • M. A. Simanjuntak, J. Imberger, K. Nakayama

    The paper describes the effect of a stair-step representation of bottom topography, common in most numerical models, on the propagation of internal waves in a geophysical flow. An analytical solution was used to predict the effect of stair-step and piecewise linear representations of topography on the reflection and transmission of internal waves. The Estuary Lake and Coastal Model (ELCOM) was used to simulate the transmission of a train of small-amplitude internal gravity waves propagated along a variable depth rectangular channel containing a linearly stratified fluid. The effect of the different obstacle approximations was examined in terms of the interference of the resulting wave number content, and hence the associated reflection coefficients, which could be directly compared to the analytical theory. It was shown that for Gaussian obstacles of varying lengths and heights, the full bottom cells and partial bottom cells solutions from ELCOM agree with the stair-step and piecewise linear solutions from the theory, respectively. It was shown that when Gaussian obstacles with weak slopes are represented by stair steps, an aliasing that is similar to that in discrete Fourier transform can occur, resulting in reflection coefficients that are much higher than the exact solution. On the other hand, piecewise linear approximations produce significantly attenuated aliasing. An immersed boundary technique that enforces a no-flux condition at the actual sloping bottom, similar to that of the analytical solution, is found not to produce better numerical results.

    AMER GEOPHYSICAL UNION, Dec. 2009, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 114, 1 - 21, English

    [Refereed]

    Scientific journal

  • 潜堤上における非線形内部波の伝搬特性

    柿沼太郎, 山下啓, 中山恵介

    Nov. 2009, 海岸工学論文集, 56, 66 - 70, Japanese

    [Refereed]

    Scientific journal

  • Reproduction of flow over sand waves using the variation principle

    Nakayama K, T. Kakinuma, D. Horimatsu, Y. Sugawara, Y. Maruya, Y. Yonome

    Sep. 2009, River, Estuary and Coastal Morphodynamics, 6, 183 - 188, English

    [Refereed]

    Scientific journal

  • A numerical study on propagation of nonlinear internal waves

    Kakinuma, T, Yamashita, K, Nakayama, K

    Jul. 2009, Proc. 5th Int. Conf. on Asian and Pacific Coasts, 3, 208 - 214, English

    [Refereed]

    Scientific journal

  • 東京湾スケールの流動が京浜運河に与える影響評価

    堀松大志, 中山恵介, 岡田知也, 古川恵太, 目淑範

    Jul. 2009, 海洋開発論文集, 25, 1041 - 1046, Japanese

    [Refereed]

    Scientific journal

  • 環境流体解析を目的としたオブジェクト指向型流体モデルの開発と検証

    新谷哲也, 中山恵介

    Mar. 2009, 水工学論文集, 53, 1267 - 1272, Japanese

    [Refereed]

    Scientific journal

  • 斜面上での内部波の砕波形態と物質輸送

    中山恵介, 角谷和成, 古川恵太, 宮澤巧, 山敷庸亮, 丸谷靖幸

    Mar. 2009, 水工学論文集, 53, 1321 - 1326, Japanese

    [Refereed]

    Scientific journal

  • 変分原理を用いた河床波上の流れの再現とその適用性

    中山恵介, 堀松大志, 柿沼太郎, 菅原庸平, 丸谷靖幸, 目淑範

    Mar. 2009, 水工学論文集, 53, 1087 - 1092, Japanese

    [Refereed]

    Scientific journal

  • 網走湖における内部ケルビン波と風応力の影響評価

    中山恵介, 堀松大志, 清水健司, 丸谷靖幸, 角谷和成, 早川博, 岡田知也, 目淑範

    Mar. 2009, 水工学論文集, 53, 1285 - 1290, Japanese

    [Refereed]

    Scientific journal

  • KAKINUMA Taro, YAMASHITA Kei, NAKAYAMA Keisuke

    Internal waves propagating over a submerged breakwater in a two-layer system are numerically simulated using a set of nonlinear internal-wave equations derived on the basis of a variational principle without any assumptions concerning wave nonlinearity and dispersion. When an internal-wave crest starts wave disintegration after passing over an offshore shoulder of submerged breakwater, both the horizontal velocity and dynamic pressure below the internal-wave crest show a remarkable distribution or a remarkable curvature of distribution in the vertical direction with wave dispersion. Over a submerged breakwater where the width of the breakwater crown is short or the lower-layer depth is deep over the breakwater crown, the crests of internal waves do not show wave disintegration.

    Japan Society of Civil Engineers, 2009, PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 65 (1), 66 - 70, English

  • Sugawara Yohei, Nakayama Keisuke, Yamamura Satoru

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, 2009, Proceeding of Annual Conference, 22, 60 - 60, Japanese

  • 東京湾の湾奥底層DO濃度に対する強風イベントの統計的解析

    中山恵介, 中尾隆志, Murugesu Sivapalan, 武村圭史朗, 佐藤千鶴, 古川恵太

    Mar. 2008, 水工学論文集, 53, 193 - 198, Japanese

    [Refereed]

    Scientific journal

  • Modeling of dissolved oxygen in an enclosed bay with sill

    T. Okada, NAKAYAMA KEISUKE

    Dec. 2007, Journal of Environmental Engineering - ASCE, 133 (4), 447 - 453, English

    [Refereed]

    Scientific journal

  • A numerical study on internal waves induced by a typhoon around a continental shelf

    T. Kakinuma, NAKAYAMA KEISUKE

    Dec. 2007, Hydrological Research Letters, 62, 574 - 590, English

    [Refereed]

    Scientific journal

  • 斜面上での内部波の砕波機構と残差流

    中山恵介, 古川恵太, 宮澤功, 山敷庸亮

    Nov. 2007, 海岸工学論文集, 55, 376 - 380, Japanese

    [Refereed]

    Scientific journal

  • 渦度を考慮した非線形波動方程式による表面波及び内部波の数値解析

    柿沼太郎, 中山恵介

    Nov. 2007, 海岸工学論文集, 55, 6 - 10, Japanese

    [Refereed]

    Scientific journal

  • 岡田知也, 高尾敏幸, 中山恵介, 古川恵太

    We calculated the monthly residence time of seawater in the inner bay of Tokyo Bay during August 2002 to June 2003 and compared it with a monthly residence time of seawater averaged from 1947 to 1974. The residence time of seawater was calculated by dividing the volume of the inner bay by an exchange rate between the inner bay and the outer bay. The exchange rate was calculated by using the monthly averaged salinity in the inner bay and the outer bay, and freshwater discharge in the inner bay. Between the years of 1947 to 1974, estimations from past studies were used to calculate the average monthly salinity. During August 2002 to June 2003, insitu salinity measurements were conducted 22 times at 27 stations within Tokyo Bay. The freshwater discharge into the inner bay was calculated from the catchment area precipitation and water mass imported from the neighboring catchment area for both data sets. From the results, the residence time of seawater during 2002 consisted of an annual mean of 31 days, with seasonal residence times of 19 days during summer and 43 days during winter. On the other hand, during 1947-1974, the mean annual residence time of seawater was 48 days, with summer and winter seasonal durations of 28 days and 79 days respectively. Thus seawater residence time in the inner bay during 2002 was greatly reduced them previous long-term estimations, by approximately 35%.

    Japan Society of Civil Engineers, Nov. 2007, 土木学会論文集, 63 (1), 67 - 72, Japanese

    [Refereed]

    Scientific journal

  • アオコ流動モデルを用いた天竜川の藍藻Microcystis細胞濃度の時間変動予測

    片上幸美, 中山恵介, 横山淳史, 本間隆満, 朴虎東

    Nov. 2007, 陸水学会誌, 68 (2), 241 - 251, Japanese

    [Refereed]

    Scientific journal

  • 東京湾奥における底層DOに対する風および河川流入の影響評価

    中山恵介, 佐藤千鶴, 古川恵

    Jul. 2007, 海洋開発論文集, 24, 633 - 638, Japanese

    [Refereed]

    Scientific journal

  • 芝浦運河 海の顔・川の顔調査

    佐藤千鶴, 古川恵太, 中山恵介

    Jul. 2007, 海洋開発論文集, 24, 763 - 768, Japanese

    [Refereed]

    Scientific journal

  • Development of a conceptual model for dissolved oxygen concentrations considering flood event effects in Tokyo Bay

    C. Satoh, K. Nakayama, Y. Yamashiki, T. Kanasashi, K. Miyazawa

    Mar. 2007, Annual Journal of Hydraulic Engineering, JSCE, 52, 199 - 204, Japanese

    [Refereed]

    Scientific journal

  • Numerical simulation of internal waves using a set of fully nonlinear internal-wave equations

    T. Kakinuma, K. Nakayama

    Mar. 2007, Annual Journal of Hydraulic Engineering, JSCE, 52, 169 - 174, Japanese

    [Refereed]

    Scientific journal

  • 一様な斜面上で砕波する内部ケルビン波により誘起される流れ

    中山恵介, 宮澤巧, 山敷庸介, 宮澤兼佑, 金刺俊之

    Mar. 2007, 水工学論文集, 52, 1385 - 1390, Japanese

    [Refereed]

    Scientific journal

  • A numerical study on stratified flows induced by a typhoon in a bay and around a continental shelf

    Taro Kakinuma, Keisuke Nakayama

    CHINA OCEAN PRESS, 2007, ASIAN AND PACIFIC COASTS 2007, 5, 295 - +, English

    [Refereed]

    International conference proceedings

  • kanesashi toshiyuki, yamashiki yousuke, miyazawa takumi, satou chiduru, nakayama keisuke

    The effect of Tama river inflow into Tokyo Bay on dissolved oxygen in bottom layer has been analyzed using numerical simulation by ELCOM- CAEDYM and field observation. The result implied that the Tama River inflow may contribute the decrease of dissolved oxygen, however further evaluation should be made for further evaluation.

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, 2007, Proceeding of Annual Conference, 20, 88 - 88, Japanese

  • Numerical study on the flow characteristics of tidal jets induced by a tidal-jet-generator

    J. C. Parka, T. Okada, K. Furukawa, NAKAYAMA KEISUKE

    Dec. 2006, Ocean Engineering, 33 (14), 1896 - 1918, English

    [Refereed]

    Scientific journal

  • Comparisons of CIP, compact and CIP-CSL2 schemes for reproducing internal solitary waves

    NAKAYAMA KEISUKE

    Dec. 2006, International Journal for Numerical Methods in Fluids, 51, 197 - 219, English

    [Refereed]

    Scientific journal

  • 2003年東京湾に発生した繊毛虫Mesodinium rubrumによる赤潮と水生生物の大量死の連関に関する調査事例

    古川恵太, 中山恵介, 水尾寛己

    日本沿岸域学会, Dec. 2006, 沿岸域学会論文集, 18 (4), 67 - 77, Japanese

    [Refereed]

    Scientific journal

  • 台風により大陸棚近傍に生成される内部波の数値解析

    柿沼太郎, 中山恵介

    Nov. 2006, 海岸工学論文集, 53, 361 - 365, Japanese

    [Refereed]

    Scientific journal

  • 東京湾における季節特性を考慮した湾内流動の再現計算

    五十嵐学, 中山恵介

    Jul. 2006, 海洋開発論文集, 22, 829 - 834, Japanese

    [Refereed]

    Scientific journal

  • 湾口部にシルをもつ湾における底層貫入とDO濃度に関する観測と数値実験

    中山恵介, 岡田知也

    Jul. 2006, 海洋開発論文集, 22, 817 - 822, Japanese

    [Refereed]

    Scientific journal

  • 東京湾奥における出水時の河川水挙動に関する基礎的研究

    西田有佑, 中山恵介, 石川忠晴

    Jul. 2006, 海洋開発論文集, 22, 793 - 798, Japanese

    [Refereed]

    Scientific journal

  • 河口部に設置された円柱による河口周辺での乱れエネルギーに関する検討

    中山恵介, 岡田知也, 古川恵太

    Mar. 2006, 水工学論文集, 50, 1387 - 1392, Japanese

    [Refereed]

    Scientific journal

  • 円柱による乱れが河口の塩水侵入に与える影響評価

    中山恵介, 岡田知也, 古川恵太

    2006, 水工学論文集, 50, 1378 - 1392

  • Mechanism responsible for fortnightly modulations in estuarine circulation in Tokyo Bay

    NAKAYAMA KEISUKE, OKADA TOMONARI, NOMURA MORIHIRO

    Dec. 2005, Estuarine Coast and Shelf Science, 64, 459 - 466, English

    [Refereed]

    Scientific journal

  • 強風の吹き寄せにより密度成層水域に生成する流れ場の 3 次元数値計算

    柿沼太郎, 中山恵介

    Nov. 2005, 海岸工学論文集, 52, 306 - 310, Japanese

    [Refereed]

    Scientific journal

  • 斜面に連続的に作用する内部界面の理論解の適用性の検討

    中山恵介, Jorg Imberger

    Nov. 2005, 土木学会論文集, 789, 59 - 71, Japanese

    [Refereed]

    Scientific journal

  • 河道モデルと沿岸流動モデルの統合とその必要性に関する検討

    中山恵介, Dushmanta Dutta, 田中岳, 岡田知也

    Nov. 2005, 水文水資源学会誌, 18 (4), 390 - 400, Japanese

    [Refereed]

    Scientific journal

  • Modeling the effect of stratification on sediment deposition

    Nakayama K

    Sep. 2005, River, Estuary and Coastal Morphodynamics, 4, 1027 - 1034, English

    [Refereed]

    Scientific journal

  • 東京湾における散逸率の縦断分布と鉛直混合

    中山恵介, 岡田知也

    Jul. 2005, 海洋開発論文集, 21, 379 - 384, Japanese

    [Refereed]

    Scientific journal

  • 東京湾の湾奥における時計回りの循環と収束現象の解明

    中山恵介, 芝口芳行, 日向博文, 石川忠晴

    Mar. 2005, 水工学論文集, 49, 1297 - 1302, Japanese

    [Refereed]

    Scientific journal

  • 東京湾湾口部におけるフロント形成過程の究明

    中山恵介, 清木荘一郎, 石川忠晴, Alex S.J. Wyatt

    Mar. 2005, 水工学論文集, 49, 1291 - 1296, Japanese

    [Refereed]

    Scientific journal

  • A Comparative Analysis of River Flow Modeling in an Urban River Basin in Japan Using Lumped and Physically Based Approaches

    Keisuke Nakayama, Dutta Dushmanta, Gaku Tanaka, Fathanha Khanam

    2005, MTERM International Conference, 207 - 214, English

    [Refereed]

    International conference proceedings

  • 固定グリッドにおいて遡上波を追跡する計算手法の開発

    中山恵介, 工藤健太郎, 石川忠晴

    Nov. 2004, 海岸工学論文集, 51, 16 - 20, Japanese

    [Refereed]

    Scientific journal

  • 荒川河口域における潮差変動に伴うChlorophyll a分布および河川流入負荷量の変動

    岡田知也, 中山恵介

    Nov. 2004, 土木学会論文集, 754, 33 - 50, Japanese

    [Refereed]

    Scientific journal

  • 2002年東京湾の海水の滞留時間とマルチボックス鉛直1次元モデルを用いた再現計算

    高尾敏幸, 岡田知也, 中山恵介, 古川恵太

    Mar. 2004, 水工学論文集, 48, 1243 - 1248, Japanese

    [Refereed]

    Scientific journal

  • 高瀬川の浅瀬が塩水遡上に与える影響について

    和光一紀, 中山恵介, 石川忠晴

    Mar. 2004, 水工学論文集, 48, 793 - 798, Japanese

    [Refereed]

    Scientific journal

  • 2成層場におけるソリトンに対する新たなスキームの適用と検討

    中山恵介

    Mar. 2004, 水工学論文集, 48, 1219 - 1224, Japanese

    [Refereed]

    Scientific journal

  • 移流拡散モデルを用いた天竜川の藍藻Microcystisの動態解析

    片上幸美, 中山恵介, 金昊燮, 米塚佐代子, 朴虎東

    Nov. 2003, 陸水学会誌, 64 (2), 121 - 131, Japanese

    [Refereed]

    Scientific journal

  • 有限要素CIP-mスキームを用いた流況予測シミュレーション

    中山恵介, 森下正志, 岡田知也

    Nov. 2003, 計算工学講演会論文集, 8, 1 - 4, Japanese

    [Refereed]

    Scientific journal

  • 斜面に連続的に作用する内部波の砕波と残差流

    中山恵介, Jorg Imberger

    Nov. 2003, 海岸工学論文集, 50, 141 - 145, Japanese

    [Refereed]

    Scientific journal

  • 荒川河口域にけるChl-aの鉛直分布

    岡田知也, 中山恵介

    Nov. 2002, 海岸工学論文集, 49, 1021 - 1025, Japanese

    [Refereed]

    Scientific journal

  • 総合的内湾水質評価モデルの構築と東京湾への適用

    岡田知也, 中山恵介, 宮野仁, 古川恵太

    Nov. 2002, 海岸工学論文集, 49, 1051 - 1055, Japanese

    [Refereed]

    Scientific journal

  • 二枚貝が優占する湖沼の水塊形成に関する数値解析

    中村由行, 奥宮英治, 中山恵介

    Nov. 2002, 海岸工学論文集, 49, 1031 - 35, Japanese

    [Refereed]

    Scientific journal

  • 湖沼の平面的な水塊分布構造に及ぼす水表面熱収支の影響

    中村由行, 奥宮英治, 中山恵介

    Nov. 2001, 海岸工学論文集, 48, 1051 - 1055, Japanese

    [Refereed]

    Scientific journal

  • 夏期の東京湾湾奥における表層の植物プランクトンに対する底層栄養塩の影響

    岡田知也, 中山恵介, 野村宗弘, 古川恵太

    Nov. 2001, 海岸工学論文集, 48, 1086 - 1090, Japanese

    [Refereed]

    Scientific journal

  • 内湾における環境問題の展開と環境シミュレーション

    古川恵太, 岡田知也, 中山恵介, 細川恭史

    Nov. 2001, 海洋工学シンポジウム, 16, 43 - 48, Japanese

    [Refereed]

    Scientific journal

  • 内湾の環境評価を目指したMEL1D-MBモデルの構築と東京湾への適用

    中山恵介, 岡田知也, 宮野仁, 古川恵太

    Nov. 2001, 海洋工学シンポジウム, 16, 59 - 66, Japanese

    [Refereed]

    Scientific journal

  • 融雪を考慮した山地流出モデルに関する研究

    中山恵介, 伊藤哲, 藤田睦博, 斎藤大作

    Nov. 2001, 土木学会論文集, 691, 25 - 41, Japanese

    [Refereed]

    Scientific journal

  • Internal wind waves and snow clouds on a mountain slope

    K. Nakayama, D. Saitoh

    Nov. 2001, Journal of Hydroscience and Hydraulic Engineering, 19 (2), 105 - 117, English

    [Refereed]

    Scientific journal

  • 東京湾湾奥部におけるChl-a(植物プランクトン量)空間分布評価モデルに関する検討

    岡田 知也, 中山 恵介, 野村 宗弘

    国土交通省港湾技術研究所, Jun. 2001, 港湾技研資料, (1003), 1 - 21, Japanese

  • 閉鎖性内湾の底層溶存酸素濃度に対する湾口防波堤の影響

    岡田 知也, 中山 恵介, 宮野 仁

    国土交通省港湾技術研究所, Jun. 2001, 港湾技研資料, (1004), 1 - 15, Japanese

  • 界面渦等により不連続化した流れ場再現プログラムCIP-m-FEMの開発

    中山 恵介, 岡田 知也

    国土交通省港湾技術研究所, Mar. 2001, 港湾技研資料, (989), 1 - 15, Japanese

  • 湖沼の物質循環に及ぼす夜間の水面冷却の影響

    奥宮英治, 中村由行, 中山恵介, 井上徹教, 石飛裕

    Mar. 2001, 水工学論文集, 45, 1147 - 1152, Japanese

    [Refereed]

    Scientific journal

  • 常射流混在場における有限要素CIP-mスキームの構築

    中山恵介, 森下正志, 岡田知也, 古川恵太, 安原晃, 中村裕一

    Mar. 2001, 水工学論文集, 45, 595 - 600, Japanese

    [Refereed]

    Scientific journal

  • 大船渡湾における底層DO濃度の変動に及ぼす湾外の影響

    岡田知也, 中山恵介, 日比野忠史, 細川恭史, 古川恵太

    Nov. 2000, 海岸工学論文集, 47, 1041 - 1045, Japanese

    [Refereed]

    Scientific journal

  • 大潮, 小潮期における湾外水の影響

    中山恵介, 岡田知也, 野村宗弘, 日比野忠史, 細川恭史, 古川恵太

    Nov. 2000, 海岸工学論文集, 47, 421 - 425, Japanese

    [Refereed]

    Scientific journal

  • 内湾域の水環境に影響を及ぼす物理的要因に関する考察-瀬戸内海総合水質調査データによる解析-

    宮野仁, 日比野忠史, 中山恵介, 岡田知也, 細川恭史, 浅井正, 日比野 忠史

    01 Jun. 2000, 港湾技術研究所報告, 39 (2), 47 - 72

    [Refereed]

    Scientific journal

  • 大船渡湾における湾外水の密度変動が湾内水環境に及ぼす影響の定量的評価

    岡田知也, 中山恵介, 日比野忠史, 細川恭史, 日比野 忠史

    国土交通省港湾技術研究所, 01 Jun. 2000, 港湾技術研究所報告, 39 (2), 73 - 98, Japanese

    [Refereed]

    Scientific journal

  • 湾内外の密度差による湾口部での流出入機構

    日比野忠史, 岡田知也, 中山恵介

    Mar. 2000, 水工学論文集, 44, 945 - 950, Japanese

    [Refereed]

    Scientific journal

  • 樹林群を考慮した浅水流モデル

    中山恵介, 堀川康志, 江島敬三

    Mar. 2000, 水工学論文集, 44, 801 - 806, Japanese

    [Refereed]

    Scientific journal

  • 成層場における固液混相流LESモデルの開発

    中山恵介

    Mar. 2000, 水工学論文集, 44, 879 - 884, Japanese

    [Refereed]

    Scientific journal

  • 東京湾における成層期の流れ場

    日比野忠史, 中山恵介, 岡田知也

    Mar. 2000, 水工学論文集, 44, 1056 - 1060, Japanese

    [Refereed]

    Scientific journal

  • Mohamed Elzeir, Tadashi Hibino, Keisuke Nakayama

    A two-dimensional finite-element model using depth-averaged Navier-Stokes equations with primitive variables is used to simulate flow in Kanmon Strait, an important navigation channel in the Japanese archipelago. It is concluded from this study that the strait, like all narrow water bodies connecting two open seas, reflects most of the energy of any wave propagating from one open sea and allows very small part of the energy to be transmitted through the narrow channel. Hence, a steep water surface gradient is generated inside the strait producing high velocities. The model, like other depth-averaged models, reasonably predicts water level and velocity direction and phase. However, they underpredict velocity values because they do not take into account effect of secondary currents.

    2000, Coastal Engineering 2000 - Proceedings of the 27th International Conference on Coastal Engineering, ICCE 2000, 276, X3861 - 3869, English

    [Refereed]

    International conference proceedings

  • Cold air flow and simulation of snow clouds

    K. Nakayama, K. Hasegawa, M. Fujita

    Dec. 1999, Journal of Hydroscience and Hydraulic Engineering, 17 (2), 127 - 138, English

    [Refereed]

    Scientific journal

  • LESモデルによる水平面上張り出しプルームの解析

    中山恵介, 佐藤圭洋

    Nov. 1999, 土木学会論文集, 628, 97 - 114, Japanese

    [Refereed]

    Scientific journal

  • 射流場におかれた円柱周辺の流れの解析

    中山恵介, 堀川康志, 三上卓哉

    Mar. 1999, 水工学論文集, 43, 365 - 370, Japanese

    [Refereed]

    Scientific journal

  • 矩形グリッドを用いた山地流出解析

    中山恵介, 伊藤哲, 藤田睦博

    Mar. 1999, 水工学論文集, 43, 31 - 36, Japanese

    [Refereed]

    Scientific journal

  • 内部波が山地斜面の大気に及ぼす影響

    中山恵介, 斎藤大作

    Mar. 1999, 水工学論文集, 43, 257 - 262, Japanese

    [Refereed]

    Scientific journal

  • A study on a wind field when a cold air flow that causes snowfall around Sapporo

    K. Nakayama, K. Hasegawa, M. Fujita

    Dec. 1998, Journal of Hydroscience and Hydraulic Engineering, 16 (1), 9 - 25, English

    [Refereed]

    Scientific journal

  • A numerical study on a cold air flow causing the formation of snow clouds over Sapporo City

    K. Nakayama, K. Hasegawa, M. Fujita

    Dec. 1998, Journal of Hydroscience and Hydraulic Engineering, 16 (2), 35 - 48, English

    [Refereed]

    Scientific journal

  • 冬期石狩湾における陸からの冷気流フロント上に発生する降雪雲観測

    中山恵介, 長谷川和義, 藤田睦博

    Nov. 1998, 土木学会論文集, 593 (593), 1 - 10, Japanese

    [Refereed]

    Scientific journal

  • 降雪をともなう冷気流に関する実験および数値計算予測

    中山恵介, 中嶌一彦, 長谷川和義, 藤田睦博

    Nov. 1998, 土木学会論文集, 607, 1 - 17, Japanese

    [Refereed]

    Scientific journal

  • 陸から海上へ張り出す冷気流と雪雲発生予測に関する研究

    中山恵介, 長谷川和義, 藤田睦博

    Mar. 1998, 水工学論文集, 42, 31 - 36, Japanese

    [Refereed]

    Scientific journal

  • CIP法を用いた浅水流方程式の数値計算手法の開発

    中山恵介, 佐藤圭洋, 堀川康志

    Mar. 1998, 水工学論文集, 42, 1159 - 1164, Japanese

    [Refereed]

    Scientific journal

  • 全流域を矩形グリッドで覆いSGS効果を考慮した浸透流方程式を用いた流出予測

    中山恵介, 伊藤哲

    Mar. 1998, 水工学論文集, 42, 1141 - 1146, Japanese

    [Refereed]

    Scientific journal

  • 雪雲発生要因である冷気流に関する数値実験的研究

    中山恵介, 中嶌一彦, 長谷川和義, 藤田睦博

    Mar. 1997, 水工学論文集, 41, 19 - 134, Japanese

    [Refereed]

    Scientific journal

  • 冬期石狩湾において豪雪をもたらす冷気流張り出しに関する研究

    中山恵介, 長谷川和義, 藤田睦博

    Nov. 1996, 土木学会論文集, 539, 31 - 42, Japanese

    [Refereed]

    Scientific journal

  • 札幌周辺に豪雪をもたらす冷気流発生時における風の場に関する研究

    中山恵介, 長谷川和義, 藤田睦博

    Mar. 1996, 水工学論文集, 40, 267 - 272, Japanese

    [Refereed]

    Scientific journal

  • 冬期石狩湾における鉛直断面内の冷気流形状に関する研究

    中山恵介, 長谷川和義, 藤田睦博

    Mar. 1995, 水工学論文集, 39, 177 - 182, Japanese

    [Refereed]

    Scientific journal

  • ANALYSIS OF WIND FIELDS IN WINTER BY USING AMEDAS AND CONSIDERING TOPOGRAPHY

    K NAKAYAMA, K HASEGAWA

    INT ASSOC HYDROLOGICAL SCIENCES, 1994, SNOW AND ICE COVERS: INTERACTIONS WITH THE ATMOSPHERE AND ECOSYSTEMS, (223), 177 - 186, English

    [Refereed]

    International conference proceedings

  • Yasuyuki Maruya, Keisuke Nakayama, Masafumi Sasaki, Katsuaki Komai

    Mar. 2023, Journal of Environmental Sciences

    Scientific journal

  • Keisuke Nakayama, Katsuaki Komai, Keisuke Ogata, Toshiro Yamada, Yukinobu Sato, Fumiya Sano, Shintarou Horii, Yuichiro Somiya, Etsuko Kumamoto, Yoichi Oyama

    AbstractAegagropila linnaei is a freshwater green alga, which at one time was distributed widely in the northern hemisphere. The aggregate often forms beautiful spherical shapes known as “lake balls” or “Marimo”. The population of Marimo has been rapidly decreasing worldwide, and today the large Marimo, with a diameter of more than 12 cm, exit only in Lake Akan in Japan. However, how Marimo grow and maintain their unique spherical shape in natural habitats remains unsolved. Here we show that Marimo are “polished” into spheres by the rotation induced by wind waves. Such a process enhances the water exchange between the interior and exterior of the Marimo, thereby recycling nutrients for growth. Our results provide an intriguing model of a physical environment interacting with biological processes in a self-sustaining ecosystem. We also demonstrate that Marimo have a spherical annual ring structure, and their growth rate is associated with ice cover. The balance between the ecology of Marimo and the water environment in Lake Akan is highly vulnerable and at risk of irreversible degradation. We must endeavor to rescue Marimo from the fate of a "canary in the coal mine" of global climate change.

    Springer Science and Business Media {LLC}, Dec. 2021, Scientific Reports, 11 (1), English

    Scientific journal

  • KOMORI Hiroto, XIONG Bing, SAITO Naoki, HAO Lin, CHI Baixin, YANO Shinichiro, KOMAI Katsuaki, NAKAYAMA Keisuke

    Regarding the reduction of atmospheric CO2, the function of CO2 absorption in coastal areas has been drawing attention. In this study, we developed a numerical model of pCO2 dynamics considering effects of freshwater inflow based on the results of field observation in the Yatsushiro Sea, to obtain the basic knowledge about CO2 dynamics in coastal areas. The model was able to reproduce well the tempo-spatial distribution of pCO2 and the distribution of salinity and water temperature under different stratification conditions. From the results of the hindcast simulation, it was confirmed that the amount of CO2 absorbed around the estuary fluctuated greatly spatiotemporally with the big flood. Furthermore, the following two effects of the freshwater inflow on the dynamics of CO2 in the coastal area are confirmed as follows: i) After flooding, CO2 release can be promoted by the suface freshwater capping; and ii) After mixing of freshwater and seawater, CO2 absorption can be promoted by photosynthesis due to blooming of phytoplankton in the surface layer.

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77 (2), I_847 - I_852, Japanese

  • YAGI Jumpei, MURATA Yoshiyuki, YOSHIMURA Hideto, FUJITA Ichiro, NAKAYAMA Keisuke

    It has been observed that a periodic water surface oscillation ocurrs downstream of a drop structure with a trench at specific hydraulic and geometric conditions. In order to establish a relationship governing the oscillation frequency, a number of experiments using flow visualization and image analysis techniques were conducted. As a result, we proposed a Strauhal number specific to the oscillating hydraulic jump. In addition, a numerical simulations based on SST 𝑘-𝜔 model was executed to successfully simulate time varying oscillating flow comparable to the experiment.

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 77 (2), I_871 - I_876, Japanese

  • TASHITA Kento, NAKAYAMA Keisuke, SHINTANI Tetsuya

    In lakes and the ocean, pycnocline is formed due to solar radiation and inflow into the coastal area, on which internal waves are generated by external forces, such as wind stress and tide. Internal waves propagate and break over a topographical slope, resulting in the long-term transport of nutrients, methane, carbon, hypoxia, and other water quality components and the deterioration of the ecological system. Internal solitary waves are revealed to have considerable kinetic energy and affect mass transport. Among internal solitary waves, "breather" is found to exist in a three-layer fluid, but the mechanism of the breather breaking over a slope remains unsolved. Thus, this study aims to clarify how breathers deform over the topographical change and break on a uniform slope by using a three-dimensional numerical model. We revealed that the classification for an internal solitary wave breaking is successfully applied to categorize the breaking type of breathers over a slope.

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77 (2), I_343 - I_348, Japanese

  • IWATA Ryo, NAKAYAMA Keisuke, SATO Takahiro, SHINTANI Tetsuya

    In a two-layer fluid, when pycnocline thickness is negligible, an internal solitary wave (ISW) breaking over a slope can be categorized into four breaker types: surging, collapsing, plunging, and fission breakers. The latest classification into four breaker types is based on wave slope, bottom slope gradient and an internal Reynolds number. However, it remains unsolved if this classification can categorize the breaking of an ISW under thick pycnocline conditions. This study uses numerical simulations to investigate the applicability of the classification under changing pycnocline thickness. We found that the classification can categorize all breaker types even when pycnocline thickness varies. Additionally, thicker pycnoclines result in more significant energy loss and onshore mass transport energy loss due to ISW breaking.

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 77 (1), 59 - 73, Japanese

  • HAMADA Takuya, YOSHIMURA Hideto, FUJITA Ichiro, NAKAYAMA Keisuke

    The surface velocity coefficient is the value that converts the surface velocity into the depth-averaged velocity when observing the discharge, and 0.85 is treated as the standard value in Japan. In recent years, surface velocity measurement by STIV is widely used, but only surface flow information can be obtained. Therefore, it is important to properly determine the coefficient when estimating the discharge. In this paper, we focused on the situation where the water depth gradually changes due to the formation of sandbars. We conducted flume experiments to examine the response characteristics of the surface velocity and the surface velocity coefficient caused by changes in the riverbed slope. As a result, it was shown that the change of the correction coefficient is not symmetrical with respect to the riverbed topography, and that the coefficient decreases sharply on the downstream side of the sandbar because the influence of negative acceleration is large. The above characteristics are verified through numerical simulations as well.

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 77 (2), I_877 - I_882, Japanese

  • OGATA Keisuke, NAKAYAMA Keisuke, OYAMA Yoichi, KOMAI Katsuaki, SHINTANI Tetsuya, AMANO Motoshi

    Aegagropila linnaei, Marimo, is a special natural monument of Japan and in danger of extinction. However, the formation mechanism of Marimo has been unresolved. In particular, it is needed to estimate the rotation angle of Marimo, which plays a significant role in the formation of Marimo. Numerical computation is one of the most robust techniques. Thus, we attempted to develop the Marimo model, including the Marimo's movement and its rotation. The Marimo model showed a relatively good reproducibility with the laboratory experiments in terms of rotation when the Marimo was in contact. However, when they were not in contact, the model did not reproduce well. It was also suggested that the rotational moment needs to be taken into account.

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 77 (2), I_1063 - I_1068, Japanese

  • KAWAHARA Yuki, TSAI Jeng-Wei, LIN Hiroyuki, MATSUMOTO Hiroki, HUNG Meng-chi, HSUEH Mei Li, NAKAYAMA Keisuke

    Cigu Lagoon is a famous lagoon for fish agriculture (oyster) and migration birds, where few seagrasses exist. We aim to investigate the environmental factors affecting carbon fluxes in Cigu Lagoon to understand the influence of fishery. SEM analysis was conducted to understand the influence of environmental factors on the air-sea CO2 flux. The results suggest that the CO2 flux is directly influenced by wind speed and indirectly by pH due to the influence of oysters. A three-dimensional environmental model, Fantom, was applied to investigate the effect of the wind on DIC at the water surface. It was demonstrated that strong wind enhances the vertical convection in the water column, resulting in high DIC at the water surface due to the mixing with higher DIC adjacent to the sea bottom.

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 77 (2), I_841 - I_846, Japanese

  • SASAKI Daisuke, MATSUMOTO Hiroki, NAKAYAMA Keisuke, TADA Kazufumi, LIN Hao-Chi, HAMADA Takuya, SHINTANI Tetsuya

    "Blue carbon", absorbed carbon by photosynthesis in coastal and ocean ecosystem, has been paid attention to as climate change mitigation. The carbon absorption rate varies when seagrass bends due to current, suggesting the necessity of precise estimation of carbon absorption by the blue carbon ecosystem. We developed the Submerged Aquatic Vegetation model (SAV model), which combines SAV motion and its interaction with the current. Therefore, this study aims to verify the SAV model's validity by applying laboratory experiments in an open channel assuming low-density polyethylene as SAV, which agreed with the laboratory experiments.

    Japan Society of Civil Engineers, 2021, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 77 (2), I_205 - I_210, Japanese

  • 琵琶湖における高精度な流動場の解析手法の提案

    王媛, 中山恵介, 岩田遼, 新谷哲也, 速水祐一, 藤原建紀

    Sep. 2020, 土木学会年時講演会講演集, 73

  • 浅水状態の粗配置桟粗度上で生じる三角状水面波列に対するソリトン解の適用—APPLICATION OF SOLITON SOLUTION TO TRIANGULE-SHAPE WATER SURFACE WAVE SEQUENCE WITH SPARSELY DISTRIBUTED STRIP ROUGHNESS IN SHALLOW WATER

    2020, 65, Ⅰ_1063 - 1068, Japanese

  • 内部ソリトン波の砕波によるエネルギー減衰のモデル化と成層流動場の高精度な再現—ENERGY ATTENUATION MODELLING UNDER THE BREAKING OF INTERNAL SOLITARY WAVES AND REPRODUCTION OF THE STRATIFIED LAKES WITH HIGH ACCURACY

    2020, 65, Ⅰ_1399 - 1404, Japanese

  • マリモにおける弾性定数と粘性係数の推定及びMR解析—ESTIMATION OF ELASTICITY AND VISCOSITY OF MARIMOS AND MR DATA ANALYSIS

    2020, 65, Ⅰ_1267 - 1272, Japanese

  • SASAKI Daisuke, NAKAYAMA Keisuke, SHINTANI Tetsuya, TADA Kazufumi, MATSUMOTO Hiroki, KOMAI Katsuaki

    When aquatic plants deflect by waves and currents, absorption rate of dissolved inorganic carbon varies dramatically. Therefore, it is necessary to evaluate the effect of wave-current on aquatic plants. In the previous studies, there are significant problems such as not fully considering the interaction between elasticity and currents. In this study, we developed a Submerged Aquatic Vegetation model (SAV model) by including branch and using object-oriented programming that enables to analyze the accurate interaction between wave-current and aquatic plants. As a result, we estimated the values of significant parameters for SAV model from laboratory experiments. Also, Minimum Elastic Modulus of branch (MEM) is revealed to be associated with the length of branch though MEM is not affected by the flow velocity and the position of branch. It was demonstrated that the larger the branch length, the larger the MEM is needed.

    Japan Society of Civil Engineers, 2020, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 76 (2), I_1075 - I_1080, Japanese

  • WANG Yuan, NAKAYAMA Keisuke, ITO Wataru, IWATA Ryo, SHINTANI Tetsuya, HAYAMI Yuichi, FUJIWARA Tateki

    In recent years, affected by global warming, overturning is suppressed in large lakes such as Lake Biwa and the similar phenomenon is likely to occur in the future. In order to prevent such phenomenon, it is very important to reproduce the stratified lakes with high accuracy. However, the past research based on the hydrostatic pressure approximation did not take the loss of potential energy (𝐸𝑝) into consideration, and the analysis of 𝐸𝑝 is larger than reality. Therefore, this study is focused on internal solitary waves and tries to model the energy loss under hydrostatic pressure approximation. As a result, the energy loss of internal solitary waves can be modelled under hydrostatic pressure approximation successfully by using frictiontype energy loss and highly accurate analysis of the stratified lakes under hydrostatic conditions becomes possible.

    Japan Society of Civil Engineers, 2020, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 76 (2), I_1399 - I_1404, Japanese

  • IWATA Ryo, NAKAYAMA Keisuke, WANG Yuan, SHINTANI Tetsuya

    Internal solitary waves are likely to be excited by the external forces such as wind in stratified lakes and coastal areas. When the internal solitary waves break on a slope, potential energy (Ep) of the internal solitary wave tends to be lost completely. The previous studies showed that hypoxia recovers on sloping bottom boundaries in Tokyo Bay when a strong wind is given. However, Ep of internal solitary waves cannot be included in a real-scale simulation because of the hydrostatic pressure approximation. Therefore, this study aims to model the energy loss to take account the breaking of internal solitary waves on a slope. As a result, the energy loss of internal solitary waves can be modeled under hydrostatic pressure approximation successfully by using friction-type energy loss not only in laboratory scale phenomena but also in real scale phenomena, Tokyo Bay.

    Japan Society of Civil Engineers, 2020, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), 76 (2), I_780 - I_785, Japanese

  • OGATA Keisuke, NAKAYAMA Keisuke, OYAMA Yoichi, KOMAI Katsuaki, HORII Shintaro, SOMIYA Yuichiro, KUMAMOTO Etsuko

    Aegagropila linnaei are natural monuments of Japan and in danger of extinction. However, the formation of Marimos has been unresolved. For the clarification of the creation of Aegagropila linnaei, a numerical computation is one of the most powerful techniques, such as a Distinct Element Method (DEM). We attempted to estimate two significant parameters for DEM, elastic modulus and viscosity coefficients of Aegagropila linnaei by applying laboratory experiments, which revealed that two parameters are constant regardless of size and density. Furthermore, we investigated Marimos by using Magnetic Resonance Imaging, which allows non-destructive investigation of Marimos underwater. The base of Marimos is revealed to move from the outer edge to the centre of Aegagropila linnaei when they grow.

    Japan Society of Civil Engineers, 2020, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 76 (2), I_1267 - I_1272, Japanese

  • YAGI Jumpei, HIGASHIKAWA Shinya, TANI Kojiro, FUJITA Ichiro, NAKAYAMA Keisuke

    Triangular-shaped surface waves occur with large amplitude in a river during a flood. The large amplitude surface waves are concerned to cause damage to river structures. Higashikawa et al. (2019) found that the train of triangular-shaped surface waves occurs due to soliton resonance. They assumed that the propagation direction of the soliton resonance inclines to the flow direction when the modified Miles' solution is applied. In this study, we aim to derive theoretical solutions by modifying the hypothesis. As a result, our new solutions agree with the laboratory experiment results better than Higashikawa et al. (2019). Furthermore, we confirmed that triangular-shaped surface waves occur due to soliton resonance.

    Japan Society of Civil Engineers, 2020, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 76 (2), I_1063 - I_1068, Japanese

  • Masafumi Sasaki, Keisuke Nakayama, Yasuyuki Maruya

    Elsevier BV, Jul. 2022, Marine Pollution Bulletin, 180, 113792 - 113792, English

    [Refereed]

    Scientific journal

  • NAKAYAMA Keisuke, SHINTANI Tetsuya

    We propose a new geophysical flow circulation model (GeoCIRC) based on object-oriented programming to compute surface and ground water flows. In this study, we focus on an infiltration processes and illustrate the basic structure of the model. The computational domain is discretized with vertical column objects that compute vertical infiltration processes within each column. They are horizontally interconnected and compute horizontal infiltration processes. The each column object consists of layer objects of different properties and resolutions to express weather, ground and geological characteristics. As a computational example, vertical circulation due to the horizontal density difference was reproduced. Then, to verify the accuracy of the model, GeoCIRC was applied to river discharge process in the Kushiro River. The computed results showed good agreements with the CoD of 0.95 and 0.81 for the Gojukkoku and Hirosato river discharge stations, respectively.

    Japan Society of Civil Engineers, 2015, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 71 (4), I_283 - I_288, Japanese

  • NAKAYAMA Keisuke

    Many investigations related to soliton resonance with the large initial amplitude of surface waves have been done in the previous studies by using numerical computaions and laboratory experiments. However, less attention has been paid to small intitial amplitude waves in the analysis of soliton resonance. Therefore, this study aims to investigate soliton resonance with the initial amplitude of 10 % of the total water-depth for surface waves by using the fully-nonlinear and strongly-dispersive wave model. As a result, the amplification rate was found to reach to 3.6 times as large as the initial amplitude. Also, the large amplification rate was found to appear when the initial shape of a solitary wave can be modeled by the KdV theory.

    Japan Society of Civil Engineers, 2015, PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 71 (2), I_1 - I_6, Japanese

  • Shino SAKAGUCHI, Keisuke NAKAYAMA, Kenichiro KOBAYASHI

    Japan Society of Civil Engineers, 2018, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 74 (4), I_1423 - I_1428

    Scientific journal

  • Kenichiro KOBAYASHI, Keisuke NAKAYAMA, Shino SAKAGUCHI

    Japan Society of Civil Engineers, 2017, Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering), 73 (4), I_1405 - I_1410

    Scientific journal

  • Hao-Chi Lin, Jeng-Wei Tsai, Kazufumi Tada, Hiroki Matsumoto, Chih-Yu Chiu, Keisuke Nakayama

    Elsevier BV, Jan. 2022, Science of The Total Environment, 803, 150044 - 150044

    Scientific journal

  • Yamashiki Yosuke, Kanesashi Toshiyuki, Katoh Daisuke, Takano Mariko, Fujita Yuji, Miyazawa Takumi, Nakayama Keisuke

    Field observation and numerical simulation in Tokyo Bay in 2005 and 2007 are performed using TOKYO3D and ELCOM-CAEDYM respectively. It has been observed that fresh water intrusion after the storm event does not disturb stratification in Tokyo Bay, henceforth, artificial mixing should be introduced to eliminate the Oxygen-Deficient Water.

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, 2008, Proceeding of Annual Conference, 21, 42 - 42, Japanese

MISC

  • Source-region identification by adjoint frequency response analysis: an application to low-mode internal tides on the Australian North West Shelf

    Kenji Shimizu, Keisuke Nakayama

    Feb. 2020, Ocean Science Meeting 2020

  • Mobility and partitioning of heavy metals in the basin of Mellah River, Algeria

    Saadia BOURAGBA, Katsuaki KOMAI, Keisuke NAKAYAMA, Toshiyuki CHIBA

    Jan. 2020, Water and Environment Technology Conference 2019

  • Occurrence of hypoxia in a reservoir

    K. Yamamoto, S. Sakaguchi, N. Hayashi, K. Nakayama, K. Kobayashi

    Jul. 2019, AOGS Meeting

  • Influence of nutrient and fine sediment control to primary productivity by benthic attached algae in forest watershed

    Katsuaki Komai, Asami Nagao, Masanori Nunokawa, Nozomi Watanabe, Yasuyuki Maruya, Keisuke Nakayama

    2016, IWA World Water Congress and Exhibition 2016, English

    [Refereed]

    Introduction international proceedings

  • Climate Change Impact Assessment on Nutrient Discharge Using Multi-Model and Multi-Scenario of GCMs in Shiretoko

    Y. Maruya, S. Watanabe, K. Nakayama, T. Tanaka, Y. Tachikawa

    The 7th International Conference on Water Resources and Environment Research, 2016, The 7th International Conference on Water Resources and Environment Research, English

    [Refereed]

    Introduction international proceedings

  • Organic carbon transport during flood due to rainfall in a headwater catchment of Kushiro Wetland, JAPAN

    Hajime Kasama, Katsuaki Komai, Yasuyuki Maruya, Keisuke Nakayama

    2016, Libra de articulos del XXVII Congress Latinoamericano de Hydraulica, English

    [Refereed]

    Introduction international proceedings

  • Numerical solutions and simulations of surface/internal solitary waves

    Kakinuma Taro, Yamashita Kei, Nakayama Keisuke

    Kyoto University, Apr. 2015, RIMS Kokyuroku, 1946, 87 - 94, Japanese

  • Nakayama, K., Maruya, Y., Matsumoto, K., Komata, M., Komai, K., Kuwae, T.

    Since marine derived nutrients (MDN) are transported not only in river channels but also across the entire river basin, including via ground water and migratory animals, it is necessary to investigate the contribution of MDN to the forest floor (soils) in order to quantify the true role of MDN at the river ecosystem scale. This study investigated the contribution of pink (Oncorhynchus gorbuscha) and chum salmon (O. keta) to total oceanic nitrogen (TN) input across a river basin using stable isotope analysis (SIA) of nitrogen (δ15N). The contribution of TN entering the river basin by salmon was 23.8 % relative to the total amount of TN exported from the river basin, providing a first estimate of MDN export for a river basin. The contribution of nitrogen from the ocean to the river basin soils was between 22.9 and 23.8 %. Furthermore, SIA showed that the transport of oceanic TN by sea eagles (Haliaeetus spp.) was greater than that by bears (Ursus arctos), which had previously been that bears are thought to be the major animal transporter of nutrients in the northern part of Japan.

    Copernicus GmbH, 2015, Biogeosciences Discussions, 12 (7), 5535 - 5557, English

  • Identification of major suspended sediment sources using X-ray florescense analysis: the Oromushi river basin case of study

    Carlos BEITIA, Keisuke NAKAYAMA, Naofumi OHTSU, Misao YAMANE, Shintaro YAMASAKI, Saadia BOURAGBA, Yasuyuki MARUYA, Katsuaki KOMAI

    2014, Proceedings of annual conference, Japan Society of Civil Engineering, Hokkaido Branch, 71, B-44, English

    Summary national conference

  • Identification of dominant suspended sediment sources in a river basin using X-ray florescence analysis

    Carlos BEITIA, Keisuke NAKAYAMA, Naofumi OHTSU, Misao YAMANE, Shintaro YAMASAKI, Yuto YOSHIE, Yasuyuki MARUYA, Katsuaki KOMAI

    2014, Proceedings of annual conference, Japan Society of Civil Engineering, Hokkaido Branch, 70, B-24, English

    Summary national conference

  • Projection of Nutrient Discharge by Using Different Bias Correction Method for Precipitation in Shiretoko

    Y. Maruya, K. Nakayama, T. Nakaegawa, T. Inoue, M. Komata, K. Komai, Y. Tachikawa

    Asia Oceania Geosciences Society 2014, 2014, Asia Oceania Geosciences Society 2014, English

    [Refereed]

    Summary international conference

  • 安定同位体比を利用した知床における海陸の栄養循環

    佐野史弥, 中山恵介, 松本経, カルロスベイティア, 丸谷靖幸, 駒井克明, 井上徹教, 桑江朝比呂

    2014, 第27回(2014年度)水文・水資源学会総会研究発表会要旨集, p.100135, Japanese

    Summary national conference

  • 湖沼におけるメタン生成量推定手法の検討

    丸谷靖幸, 竹内友彦, 中山恵介, 佐々木正史, 駒井克昭

    2014, 第27回(2014年度)水文・水資源学会総会研究発表会要旨集, p.100094, Japanese

    Summary national conference

  • 地球規模での環境変動が知床の栄養流出に及ぼす影響評価

    丸谷靖幸, 中山恵介, 仲江川敏之, 井上徹教, 小俣雅嗣, 石田哲也, 駒井克昭

    2014, 土木学会北海道支部論文報告集, 70, B-46, Japanese

    Summary national conference

  • ラウス川流域におけるリン流出量と還元量の推定

    徳重彰倫, 中山恵介, 丸谷靖幸, 桑江朝比呂, 井上徹教, 松本経, 駒井克昭

    2014, 土木学会北海道支部論文報告集, 70, B-25, Japanese

    Summary national conference

  • 宮古湾における底泥およびアマモのモニタリング結果(2012年10月)

    岡田知也, 丸谷靖幸, 中山恵介, 古川恵太

    Sep. 2013, 国土技術政策総合研究所資料, (752), 16P, Japanese

  • 結氷した湖沼におけるメタン生成過程の解明に向けた現地観測

    小窪一毅, 丸谷靖幸, 中山恵介, 駒井克昭, 佐々木正史

    2013, 第26回(2013年度)水文・水資源学会総会研究発表会要旨集, 180 - 181, Japanese

    Summary national conference

  • 内部ケルビン波の砕波により発生する流れに関する研究

    小窪一毅, 中山恵介, 新谷哲也, 大塚淳一, 岡田知也, 渡部靖憲, 丸谷靖幸

    01 Aug. 2012, 土木学会年次学術講演会講演概要集(CD-ROM), 67th, ROMBUNNO.II-055, Japanese

  • Numerical calculation of tsunami generation and propagation considering velocity distribution or density stratification (New Developments in Study of Nonlinear Wave Phenomena)

    Kakinuma Taro, Yamashita Kei, Nakayama Keisuke

    Kyoto University, Jul. 2012, RIMS Kokyuroku, 1800, 1 - 13, Japanese

  • Sediment transportation area-weighted rate evaluation by chemical composition analysis in a river basin, using Oromushi River as case of study

    Carlos BEITIA, Keisuke NAKAYAMA, Tetsuya ISHIDA, Yasuyuki MARUYA, Katsuaki KOMAI

    2012, Proceedings of 26th annual conference, Japan Society of Hydrology and Water Resources, 164 - 165, English

    Summary national conference

  • Comparison of Water Circulation Mechanisms between the 1970s and the 2000s in Kushiro Wetland

    Y. Sugawara, Y. Maruya, K. Komai, K. Nakayama, J. Kato

    11th International Conference on Civil and Environmental Engineering, 2012, Proceedings of the 11th International Conference on Civil and Environmental Engineering, 89 - 90, English

    [Refereed]

    Introduction international proceedings

  • MRI-AGCM3.1とCMIP3のマルチ気候モデルを利用した東京湾で発生する強風の将来予測

    丸谷靖幸, 中山恵介, 仲江川敏之, 駒井克昭, 岡田知也

    2012, 第25回(2012年度)水文・水資源学会総会研究発表会要旨集, 82 - 83, Japanese

    Summary national conference

  • 釧路湿原における分布型流出モデルの再現性の検討

    大塚泰之, 丸谷靖幸, 中山恵介, 菅原庸平

    2012, 土木学会北海道支部論文報告集, 68, B-20, Japanese

    Summary national conference

  • 知床における海陸の栄養塩循環量の推定

    アイヌルアブリズ, 中山恵介, 丸谷靖幸, 井上徹教, 桑江朝比呂, 舘山一孝, 岡田知也, 加藤淳子, 石田哲也

    2012, 土木学会北海道支部論文報告集, 68, B-59, Japanese

    Summary national conference

  • 東京湾の生態系モデル開発に向けたパーシャルセルの適用

    木下直貴, 中山恵介, 新谷哲也, 丸谷靖幸

    2012, 土木学会北海道支部論文報告集, 68, B-59, Japanese

    Summary national conference

  • 異なる成層場における内部ケルビン波の斜面上での砕波

    小窪 一毅, 中山 恵介, 新谷 哲也, 丸谷 靖幸, 岡田 知也, 渡部 靖憲, Kokubo Kazuki, Nakayama Keisuke, Shintani Tetsuya, Maruya Yasuyuki, Okada Tomonari, Watanabe Yasunori

    公益社団法人土木学会北海道支部, 2011, 論文報告集, 23 (68), Japanese

  • Rainfall Analysis in Subtropical Panama

    Junko KATO, Erick VALLESTER, Reinhardt PINZON, Jose FABREGA, Jorge ESPINOSA, Keisuke NAKAYAMA, Toshiyuki NAKAEGAWA, Yasuyuki MARUYA, Katsuaki KOMAI

    2011, Proceedings in the symposium on Extreme Weather and Impact Assessments - for contributing the IPCC AR5 -, 39, English

    Summary national conference

  • Projections of Rainfall Intensity in Central America, Panama

    Carlos BEITIA, Yasuyuki MARUYA, Erick VALLESTER, Reinhardt PINZON, Jose FABREGA, Berta OLMEDO, Keisuke NAKAYAMA, Toshiyuki NAKAEGAWA, Katsuaki KOMAI

    2011, Proceedings in the symposium on Extreme Weather and Impact Assessments - for contributing the IPCC AR5 -, 40, English

    Summary national conference

  • GCMを用いた東京湾におけるDO濃度回復に関する将来予測

    丸谷靖幸, アイヌルアブリズ, 中山恵介, 仲江川敏之, 古川恵太

    2011, 土木学会年次学術講演会報告集, 66, II-195, Japanese

    Summary national conference

  • GCMを利用した東京湾における強風の将来予測

    丸谷靖幸, 中山恵介, 仲江川敏之, アイヌルアブリズ, 駒井克昭

    2011, 極端気象現象とその気候変動による影響評価に関するシンポジウム(Ⅱ)要旨集, 41, Japanese

    Summary national conference

  • 知床ラウス川からの栄養塩フラックスの推定

    アイヌルアブリズ, 加藤淳子, 丸谷靖幸, 井上徹教, 桑江朝比呂, 中山恵介

    2011, 第24回(2011年度)水文・水資源学会総会・研究発表会要旨集, P.96, Japanese

    Summary national conference

  • 知床ラウス川流域における安定同位体比を用いた海起源栄養塩の分布解析

    アイヌルアブリズ, 中山恵介, 丸谷靖幸, 桑江朝比呂, 石田哲也

    2011, 土木学会北海道支部論文報告集, 67, B-22, Japanese

    Summary national conference

  • GCM を用いた東京湾に対する風速の再現性の基礎的検討

    丸谷靖幸, 中山恵介, 仲江川敏之

    2011, 土木学会北海道支部論文報告集, 67, B-45, Japanese

    Summary national conference

  • 知床における安定同位体比を用いた栄養塩循環に関する基礎的検討

    丸谷靖幸, 中山恵介, 桑江朝比呂, Ayinuer Abulizi

    2010, 第23回(2010年度)水文・水資源学会総会・研究発表会要旨集, P.141, Japanese

    Summary national conference

  • 安定同位体比を用いた知床における栄養塩循環の基礎的検討

    小野智也, 中山恵介, 桑江朝比呂, 丸谷靖幸, アイヌルアブリズ

    2010, 土木学会北海道支部論文報告集, 66, B-38, Japanese

    Summary national conference

  • 2007年~2008年における網走湖の観測結果について

    丸谷靖幸, 中山恵介, 堀松大志, 大田見定

    2009, 土木学会北海道支部論文報告集, 65, B-28, Japanese

    Summary national conference

  • 2006年10月の洪水時における網走湖内の流動解析

    中山恵介, 堀松大志, 丸谷靖幸, 徐乃丹, 米元光明

    2009, 土木学会北海道支部論文報告集, 65, B-39, Japanese

    Summary national conference

  • 網走湖を対象とした風応力の内部ケルビン波と物質循環への影響評価

    中山恵介, 堀松大志, 角谷和成, 丸谷靖幸, 早川博

    2008, 第21回(2008年度)水文・水資源学会総会・研究発表会要旨集, P.85, Japanese

    Summary national conference

  • Nakayama Keisuke, Okada Tomonari, Furukawa Keita

    夏季における東京湾の湾央から湾奥にかけて,底層での有機物の分解に伴う酸素消費によって,底層に貧酸素水塊が発生することが良く知られており,この貧酸素水塊は,東京湾における生態系,水質環境に大きな影響を及ぼしていることから,どのようなメカニズムで底層の溶存酸素(DO)濃度が変化しているかを把握することは重要である.通常,夏季におけるエスチュアリー循環での湾内水の湾外水との交換は20日から30日であり,河川出水が生じると交換がより促進されることが知られている.そのため,河川出水が生じるとDO濃度が大きく回復する可能性がある.そこで本研究では,まず湾央の底層におけるDO濃度に着目し,河川出水イベントによる影響評価手法確率のためのDO濃度再現モデルの作成を行うことを目的とした.その結果,観測地点におけるDO濃度は,河川流入によるエスチュアリー循環の変化によって大きく変動していることが確認された.

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, 2006, Proceeding of Annual Conference, 19 (0), 65 - 65

  • 荒川河口域における混合形態に伴うChlorophyll-α動態と海域への河川流入負荷量変動

    岡田 知也, 中山 恵介

    国土技術政策総合研究所, Jun. 2003, 国土技術政策総合研究所資料, (87), 1 - 23,巻頭1〜3, Japanese

  • 環境施策に資する内湾域の総合的な環境把握を目指したMEL1D-MBモデルの構築

    古川 恵太, 中山 恵介, 岡田 知也

    国土技術政策総合研究所, Dec. 2001, 国土技術政策総合研究所研究報告, (1), 1 - 3,1〜16, Japanese

  • 小幡 一貴, 清水 武俊, 小田 琢也, 小林 弘樹, 山元 幸之助, 中山 恵介

    公益社団法人 日本水道協会, 2020, 全国会議(水道研究発表会)講演集, 2020, 174 - 175, Japanese

  • 潜堤上における非線形内部波の伝播特性 (非線形波動現象の数理と応用)

    柿沼 太郎, 山下 啓, 中山 恵介

    京都大学, Aug. 2010, 数理解析研究所講究録, 1701, 206 - 211, Japanese

  • Characterization of rare earth elements in terrestrial water and biological samples in the east Hokkaido

    篠原健人, 片岡俊徳, 駒井克昭, 尾山洋一, 中山恵介, 山田俊郎

    2021, 土木学会北海道支部論文報告集(CD-ROM), (77)

  • 外的要因が球状マリモ形成に与える影響評価のための固液混相流モデルの開発

    林典子, 中山恵介, 尾山洋一, 若菜勇, 山田俊郎, 駒井克昭

    2018, 土木学会関西支部年次学術講演会講演概要集(CD-ROM), 2018

  • 阿寒湖におけるマリモ球状化に影響を与える風の将来予測

    佐野史弥, 中山恵介, 山田俊郎, 佐藤之信, 丸谷靖幸, 駒井克昭, 尾山洋一, 若菜勇

    2016, 土木学会年次学術講演会講演概要集(CD-ROM), 71st

  • DEVELOPMENT OF SUBMERGED AQUATIC VEGETATION MODEL CONSIDERING BRANCH

    佐々木大輔, 中山恵介, 新谷哲也, 田多一史, 松本大輝, 駒井克昭

    2020, 土木学会論文集 B2(海岸工学)(Web), 76 (2)

  • ENERGY ATTENUATION MODELLING UNDER THE BREAKING OF INTERNAL SOLITARY WAVES AND REPRODUCTION OF THE STRATIFIED LAKES WITH HIGH ACCURACY

    WANG Yuan, 中山恵介, 伊藤航, 岩田遼, 新谷哲也, 速水祐一, 藤原建紀

    2020, 土木学会論文集 B1(水工学)(Web), 76 (2)

  • 釧路川流域における湿原再生に向けた栄養塩輸送量の評価手法に関する研究

    駒井克昭, 中山恵介, 河合守, 新谷哲也, 中下慎也

    2015, 土木学会年次学術講演会講演概要集(CD-ROM), 70th

  • 内部ケルビン波の砕波により誘起される水平循環

    小窪一毅, 中山恵介, 新谷哲也, 柿沼太郎, 大塚淳一, 渡部靖憲, 駒井克昭, 清水健司

    2014, 土木学会北海道支部論文報告集(CD-ROM), (70)

  • 東京湾の水質予測に与える干潟の影響

    木下直貴, 中山恵介, 新谷哲也

    2014, 土木学会北海道支部論文報告集(CD-ROM), (70)

  • 環境流体解析のための簡易Wetting and Dryingスキーム

    新谷哲也, 中山恵介, 中本篤嗣

    2012, 水工学論文集(CD-ROM), 56

  • Partial Cellを導入した塩水遡上解析

    中本篤嗣, 中山恵介, 新谷哲也

    2012, 土木学会北海道支部論文報告集(CD-ROM), (68)

  • 海面上昇を考慮した釧路湿原への塩水遡上の影響評価

    中本篤嗣, 新谷哲也, 中山恵介, 丸谷靖幸, 石田哲也, 法村賢一

    2011, 水工学論文集(CD-ROM), 55

  • 網走川において風波が塩水浸入に及ぼす影響評価

    佐久間慎雄, 中山恵介, 柿沼太郎, 新谷哲也

    2010, 土木学会北海道支部論文報告集(CD-ROM), (66)

  • コリオリを考慮した斜面上での内部波の砕波について

    福岡将太, 中山恵介, 新谷哲也, 角谷和成

    2010, 土木学会北海道支部論文報告集(CD-ROM), (66)

Books etc

  • 湿地の科学と暮らし-北のウェットランド大全

    NAKAYAMA KEISUKE

    Others, 北海道大学出版会, Apr. 2017, Japanese

    Scholarly book

  • 地形の辞典

    日本地形学連合編, 鈴木隆介編, 砂村継夫編, 松倉公憲編, NAKAYAMA KEISUKE

    Others, 朝倉書店, Feb. 2017, Japanese

    Scholarly book

  • 図説日本の海岸

    柴山知也, 茅根創編, NAKAYAMA KEISUKE

    Others, 朝倉書店, Apr. 2013, Japanese

    Scholarly book

  • The Environment in Asia Pacific Harbors

    E. Wolanski, NAKAYAMA KEISUKE

    Others, Springer, Apr. 2006, English

    Scholarly book

Association Memberships

  • 流体力学会

  • 水文水資源学会

  • AGU

  • 土木学会

Research Projects