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Seasonal overturning circulation in the Red Sea: 2. Winter circulation
Author(s) -
Yao Fengchao,
Hoteit Ibrahim,
Pratt Larry J.,
Bower Amy S.,
Köhl Armin,
Gopalakrishnan Ganesh,
Rivas David
Publication year - 2014
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2013jc009331
Subject(s) - circulation (fluid dynamics) , shutdown of thermohaline circulation , climatology , oceanography , environmental science , thermohaline circulation , geology , engineering , aerospace engineering , north atlantic deep water
Abstract The shallow winter overturning circulation in the Red Sea is studied using a 50 year high‐resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented by 1980, and the climatological mean are analyzed using model output to delineate the three‐dimensional structure and to investigate the underlying dynamical mechanisms. The horizontal model circulation in the winter of 1980 is dominated by energetic eddies. The climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24°N. The overturning is accomplished through a cyclonic recirculation and a cross‐basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model's winter overturning circulation. The simulated water exchange is not hydraulically controlled in the Strait of Bab el Mandeb; instead, the exchange is limited by bottom and lateral boundary friction and, to a lesser extent, by interfacial friction due to the vertical viscosity at the interface between the inflow and the outflow.