日本地球惑星科学連合2015年大会

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インターナショナルセッション(口頭発表)

セッション記号 A (大気水圏科学) » A-CG 大気水圏科学複合領域・一般

[A-CG07] Continental-Oceanic Mutual Interaction: Global-scale Material Circulation through River Runoff

2015年5月27日(水) 11:00 〜 12:45 201B (2F)

コンビーナ:*山敷 庸亮(京都大学大学院総合生存学館)、升本 順夫(海洋研究開発機構)、Swadhin Behera(Climate Variation Predictability and Applicability Research Program Research Institute for Global Change/JAMSTEC, 3173-25 Showa-machi, Yokohama 236-0001)、宮澤 泰正(独立行政法人海洋研究開発機構)、山形 俊男(海洋研究開発機構 アプリケーションラボ)、寶 馨(京都大学防災研究所)、座長:山敷 庸亮(京都大学大学院総合生存学館)、宮澤 泰正(独立行政法人海洋研究開発機構)、寶 馨(京都大学防災研究所)

11:00 〜 11:30

[ACG07-07] 陸域起源トレーサーの沿岸域における分散解析:内湾および開放性海岸に対する比較実験

*内山 雄介1鈴江 洋太1 (1.神戸大学大学院)

キーワード:沿岸域における分散, オイラー型パッシブトレーサー, オフライントレーサーモデル, ROMS, ダウンスケール海洋モデル, JCOPE2

Coastal marginal seas and estuaries are generally dumpsites for waster water from sewage and power plants (e.g., Uchiyama et al., 2014). Accidental leakage of toxic materials may result in serious hazardous incidents that should be predicted and assessed urgently upon the occurrence. We therefore develop an offline passive tracer model that computes 3D dispersal of arbitrary Eulerian tracers with a point source capability by exploiting 3D oceanic model reanalysis and prediction such as JCOPE2 (Miyazawa et al., 2009). The purposes of the present study are to investigate (1) reproducibility of the offline tracer dispersal against the online result, and (2) difference in spatiotemporal variability of the leaked tracers in a semi-enclosed estuary (viz., Seto Inland Sea, Japan; SIS) and in an open coast environment on the continental margin off Shizuoka Prefecture on the Pacific side of Japan.
For the first objective, we analyze with the double-nested JCOPE2-ROMS downscaling system for the entire SIS at the horizontal resolution of 600 m. The release site is chosen on the southern coast of the Iyo Sea. The tracer has been discharged for 11 days in 4 different seasons since the 1st day in Feb., May, Aug., and Nov., 2013, and tracked for 31 days after each release. Overall similarity in the dispersal pattern is obtained for both the online and offline cases, whereas some undesirable negative concentration arisen from a discrete advection scheme induces a slight deviation in the inventory of the released tracer between the two cases. Tidal oscillations enhance local dilution, while the month-long transport is dominated rather by inter-seasonal variability of the clockwise circulation of the SIS. The comparative offline tracer computation for the open coast off Shizuoka is conducted with another double-nested JCOPE2-ROMS downscaling model result for the Kuroshio region at the horizontal resolution of 1 km. The tracer release occurs near the Cape Omaezaki and is done in the same way as the SIS runs. The Kuroshio readily traps the released tracer in the offline open coast run, leading to immediate transport in the northeast direction. The seasonal difference of the tracer dispersal is apparent, depending on the locations of the Kuroshio axis.