The Red Sea outflow regulated by the Indian monsoon

Hidenori Aiki*, Keiko Takahashi, Toshio Yamagata

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


To investigate why the Red Sea water overflows less in summer and more in winter, we have developed a locally high-resolution global OGCM 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 characterized by anticyclonic (cyclonic) vorticity, as suggested from the potential vorticity difference.

Original languageEnglish
Pages (from-to)1448-1468
Number of pages21
JournalContinental Shelf Research
Issue number12-13
Publication statusPublished - 2006 Aug
Externally publishedYes


  • Coastal upwelling
  • Monsoon winds
  • Stretched-coordinate OGCM
  • Subsurface tongue

ASJC Scopus subject areas

  • Oceanography
  • Aquatic Science
  • Geology


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