Response of the Southern Benguela upwelling system to fine-scale modifications of the coastal wind - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Marine Systems Année : 2016

Response of the Southern Benguela upwelling system to fine-scale modifications of the coastal wind

Résumé

We analyze the results of a regional model of the Southern Benguela upwelling system forced by wind stress fields derived from QuikSCAT observations. Two different horizontal resolutions are considered for the wind stress: QS25 and QS50, corresponding to native 25 and 50 km grids, respectively. The differences between both products highlight the primary importance of fine-scale momentum fluxes for both the structure and intensity of the wind- and wind-curl-driven upwelling. Using QS25, we show that the coastal Ekman transport is reduced, leading to a warmer SST and a reduced oceanic coastal jet. QS25 finer wind stress curl patterns also favor the development of a stronger and shallower poleward undercurrent. The addition of a coastal wind correction to QS25 lets us investigate the possible implications of an imbalance between Ekman transport and Ekman pumping: a wind reduction in the coastal band often reduces the SST cooling, but the two mechanisms compensate each other when the characteristic length scales of the coastal upwelling and the orography-induced wind drop-off are similar.

Domaines

Océanographie

Dates et versions

hal-01575241 , version 1 (18-08-2017)

Identifiants

Citer

F. Desbiolles, Bruno Blanke, A. Bentamy, Claude Roy. Response of the Southern Benguela upwelling system to fine-scale modifications of the coastal wind. Journal of Marine Systems, 2016, 156, pp.46-55. ⟨10.1016/j.jmarsys.2015.12.002⟩. ⟨hal-01575241⟩
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