Response of Surface Wind Divergence to Mesoscale SST Anomalies under Different Wind ConditionsSource: Journal of the Atmospheric Sciences:;2019:;volume 076:;issue 007::page 2065DOI: 10.1175/JAS-D-18-0204.1Publisher: American Meteorological Society
Abstract: AbstractThe response of the atmospheric boundary layer to mesoscale sea surface temperature (SST) is often characterized by a link between wind stress divergence and downwind SST gradients. In this study, an idealized simulation representative of a storm track above a prescribed stationary SST field is examined in order to determine in which background wind conditions that relationship occurs. The SST field is composed of a midlatitude large-scale frontal zone and mesoscale SST anomalies. It is shown that the divergence of the surface wind can correlate either with the Laplacian of the atmospheric boundary layer temperature or with the downwind SST gradient. The first case corresponds to background situations of weak winds or of unstable boundary layers, and the response is in agreement with an Ekman balance adjustment in the boundary layer. The second case corresponds to background situations of stable boundary layers, and the response is in agreement with downward mixing of momentum. Concerning the divergence of the wind stress, it generally resembles downwind SST gradients for stable and unstable boundary layers, in agreement with past studies. For weak winds, a correlation with the temperature Laplacian is, however, found to some extent. In conclusion, our study reveals the importance of the large-scale wind conditions in modulating the surface atmospheric response with different responses in the divergences of surface wind and wind stress.
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contributor author | Foussard, A. | |
contributor author | Lapeyre, G. | |
contributor author | Plougonven, R. | |
date accessioned | 2019-10-05T06:51:00Z | |
date available | 2019-10-05T06:51:00Z | |
date copyright | 5/10/2019 12:00:00 AM | |
date issued | 2019 | |
identifier other | JAS-D-18-0204.1.pdf | |
identifier uri | http://yetl.yabesh.ir/yetl1/handle/yetl/4263617 | |
description abstract | AbstractThe response of the atmospheric boundary layer to mesoscale sea surface temperature (SST) is often characterized by a link between wind stress divergence and downwind SST gradients. In this study, an idealized simulation representative of a storm track above a prescribed stationary SST field is examined in order to determine in which background wind conditions that relationship occurs. The SST field is composed of a midlatitude large-scale frontal zone and mesoscale SST anomalies. It is shown that the divergence of the surface wind can correlate either with the Laplacian of the atmospheric boundary layer temperature or with the downwind SST gradient. The first case corresponds to background situations of weak winds or of unstable boundary layers, and the response is in agreement with an Ekman balance adjustment in the boundary layer. The second case corresponds to background situations of stable boundary layers, and the response is in agreement with downward mixing of momentum. Concerning the divergence of the wind stress, it generally resembles downwind SST gradients for stable and unstable boundary layers, in agreement with past studies. For weak winds, a correlation with the temperature Laplacian is, however, found to some extent. In conclusion, our study reveals the importance of the large-scale wind conditions in modulating the surface atmospheric response with different responses in the divergences of surface wind and wind stress. | |
publisher | American Meteorological Society | |
title | Response of Surface Wind Divergence to Mesoscale SST Anomalies under Different Wind Conditions | |
type | Journal Paper | |
journal volume | 76 | |
journal issue | 7 | |
journal title | Journal of the Atmospheric Sciences | |
identifier doi | 10.1175/JAS-D-18-0204.1 | |
journal fristpage | 2065 | |
journal lastpage | 2082 | |
tree | Journal of the Atmospheric Sciences:;2019:;volume 076:;issue 007 | |
contenttype | Fulltext |