126 The role of wind forcing in the formation of submesoscale coherent eddies in the Gulf of Eilat/Aqaba

Thursday, 20 June 2013
Bellevue Ballroom (The Hotel Viking)
Hilla Afargan, Weizmann Institute of Science, Rehovot, Israel; and H. Gildor

Submesoscale, cyclonic eddies have been observed using a high frequency radar system in the northern part of the Gulf of Eilat/Aqaba. These eddies appear during fall and winter months and are absent during the rest of the year, making eddy formation an intriguing feature of the circulation in the northern gulf. Using an oceanic general circulation model and a regional atmospheric model, which provides atmospheric data with high spatial and temporal variability, we investigate the role of atmospheric wind in the formation of these eddies, by analyzing three test cases in detail. For all three cases, the model simulates the development of a coherent eddy with similar characteristics as the observed ones, including width, intensity, and persistence. Generation of one of the coherent eddies occurs in a process similar to lid driven cavity flow, in which eastward currents at the southern open-boundary of the rectangular-shaped area of the head of the gulf act as the driving mechanism for cyclonic circulation within the cavity. By contrast, stronger winds contribute to eddy formation in the other test cases, suggesting that a different, wind-driven mechanism can also affect the flow.
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