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地球生命圏研究機構

SELIS セミナー

日時

2016年3月7日(月) 16:30~18:00

場所

宇宙地球環境研究所6階ミーティングスペース(617)   

講演者

            相木秀則 (宇宙地球環境研究所 陸域海洋圏生態研究部 准教授)

講演内容

「 The Red Sea outflow regulated by the Indian monsoon

  To investigate why the Red Sea water overflows less in summer and more in winter, Aiki et al. (2006) have developed a locally high-resolution global ocean model with transposed poles in the Arabian peninsula and India. Based on a series of sensitivity experiments with different sets of idealized atmospheric forcing, the present study shows that the summer cessation of the strait outflow is remotely induced by the monsoonal wind over the Indian Ocean, in particular that over the western Arabian Sea. During the southwest monsoon (May–September), thermocline in the Gulf of Aden shoals as a result of coastal Ekman upwelling induced by the predominantly northeastward wind in the Gulf of Aden and the Arabian Sea. Because this shoaling is maximum during the southwest summer monsoon, the Red Sea water is blocked at the Bab el Mandeb Strait by upwelling of the intermediate water of the Gulf of Aden in late summer. The simulation also shows the three-dimensional evolution of the Red Sea water tongue at the mid-depths in the Gulf of Aden. While the tongue meanders, the discharged Red Sea outflow water (RSOW) (incoming Indian Ocean intermediate water (IOIW)) is always characterised by anticyclonic (cyclonic) vorticity, as suggested from the potential vorticity difference.