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Somali Current rings in the eastern Gulf of Aden

Authors :
William E. Johns
Amy S. Bower
David M. Fratantoni
Hartmut Peters
Source :
Journal of Geophysical Research. 111
Publication Year :
2006
Publisher :
American Geophysical Union (AGU), 2006.

Abstract

[1] New satellite-based observations reveal that westward translating anticyclonic rings are generated as a portion of the Somali Current accelerates northward through the Socotra Passage near the mouth of the Gulf of Aden. Rings thus formed exhibit azimuthal geostrophic velocities exceeding 50 cm/s, are comparable in overall diameter to the width of the Gulf of Aden (250 km), and translate westward into the gulf at 5-8 cm/s. Ring generation is most notable in satellite ocean color imagery in November immediately following the transition between southwest (boreal summer) and northeast (winter) monsoon regimes. The observed rings contain anomalous fluid within their core which reflects their origin in the equator-crossing Somali Current system. Estimates of Socotra Passage flow variability derived from satellite altimetry provide evidence for a similar ring generation process in May following the winter-to-summer monsoon transition. Cyclonic recirculation eddies are observed to spin up on the eastern flank of newly formed rings with the resulting vortex pair translating westward together. Recent shipboard and Lagrangian observations indicate that vortices of both sign have substantial vertical extent and may dominate the lateral circulation at all depths in the eastern Gulf of Aden.

Details

ISSN :
01480227
Volume :
111
Database :
OpenAIRE
Journal :
Journal of Geophysical Research
Accession number :
edsair.doi...........8d21802676ac15996325328e01061b17
Full Text :
https://doi.org/10.1029/2005jc003338