On the width of the equatorial deep jets.

Claus, Martin , Greatbatch, R. J. , Brandt, Peter , Didwischus, Sven-Helge and Fu, Yao (2013) On the width of the equatorial deep jets. [Talk] In: EGU General Assembly 2013. , 07.-12.04.2013, Vienna, Austria .

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Abstract

The equatorial deep jets (EDJ) are a striking feature of the equatorial ocean circulation. In the Atlantic Ocean, the EDJ are associated with a vertical scale of between 300 and 700 m, a time scale of roughly 4.5 years and upward energy propagation to the surface. It has been found that the meridional width of the EDJ is roughly 1.5 times larger than expected based on their vertical scale. Here a representation of a equatorial basin mode excited in a linear shallow water model for a high order baroclinic vertical normal mode is used as a simple model for the EDJ. We argue that mixing of momentum along isopycnals can explain the enhanced width and a lateral eddy viscosity of 300 m^2s^-1 is found to be sufficient to account for the width implied by observations. Additionally, the effect of barotropic mean flow on the spatial and temporal structure of the wave field is studied. A mean flow resembling the Atlantic Equatorial Intermediate Current System with eastward jets at 2°N/S and westward flow in between results in a wave shielding of the equatorial band from adjacent regions.

Document Type: Conference or Workshop Item (Talk)
Keywords: EDJ ; Equatorial Deep Jets; tropical Atlantic; SFB754 ; equator; equatorial currents
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-TM Theory and Modeling
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
Date Deposited: 08 Jul 2013 09:48
Last Modified: 08 Jul 2013 09:48
URI: http://oceanrep.geomar.de/id/eprint/21520

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