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第310回 大気海洋物理学・気候力学セミナー のおしらせ
日 時: 7月19日(木) 9:30 - 12:00
Date : Thu., 19 Jul. 9:30−12:00
場 所: 環境科学院D201室
Place : Env. Sci. Bldg. D201
Speaker:Vivek Kishor Shilimkar (Course in Atmosphere-Ocean and Climate Dynamics/D3)
Title:On relative contribution of Pacific and Indian Oceans to the decadal variation of
Indonesian Throughflow in current climate and future climate RCP8.5 scenario.
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On relative contribution of Pacific and Indian Oceans to the decadal variation of Indonesian Throughflow in current climate and future climate RCP8.5 scenario. Vivek Kishor Shilimkar 発表要旨:
Sea surface height difference between the North-Western Pacific (NWP) and South-Eastern Indian (SEI) Ocean basin drives Indonesian Throughflow from Pacific to Indian Ocean. Studies shows that ITF played an important role in inter-basin heat transport from Pacific to Indian Ocean in recent decade, during recent hiatus period. Analysis of ORAS4 reanalysis data shows that the ITF volume transport in the Makassar Strait on the decadal time-scale co-varies with the SSH gradient between NWP and SEI ocean, with significant correlation coefficient (r>0.9). Which confirms the theory that SSH gradient has good skill in estimating the ITF changes on decadal timescale as well. From reanalysis data, we also demonstrate that, ITF changes on decadal timescale largely depends on the NWP Ocean SSH variability (>90%) and small contribution (<10%) is from the SEI Ocean. We also developed a new method to estimate the ITF transport on decadal timescale using only atmospheric wind dataset. Further, primary goal of current study is to understand the future changes in contribution of Pacific and Indian Ocean basin to the decadal variation of ITF transport. Analysis of CMIP5 historical simulation and RCP8.5 scenario projection shows increase in the contribution of SEI Ocean SSH to the decadal variation of ITF transport. This increased contribution is well explained by the increased variance in future climate. Owing to the mean climatic changes in Indian Ocean east-west SST gradient, equatorial wind-stress and thermocline depth in east Indian Ocean.
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