DOI: 10.1007/s00382-015-2583-4
Scopus记录号: 2-s2.0-84955493971
论文题名: Orographic shaping of US West Coast wind profiles during the upwelling season
作者: Renault L. ; Hall A. ; McWilliams J.C.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 46, 期: 2017-01-02 起始页码: 273
结束页码: 289
语种: 英语
英文摘要: Spatial and temporal variability of nearshore winds in eastern boundary current systems is affected by orography, coastline shape, and air-sea interaction. These lead to a weakening of the wind close to the coast: the so-called wind drop-off. In this study, regional atmospheric simulations over the US West Coast are used to demonstrate monthly characteristics of the wind drop-off and assess the mechanisms controlling it. Using a long-term simulation, we show the wind drop-off has spatial and seasonal variability in both its offshore extent and intensity. The offshore extent varies from around 10 to 80 km from the coast and the wind reduction from 10 to 80 %. We show that when the mountain orography is combined with the coastline shape of a cape, it has the biggest influence on wind drop-off. The primary associated processes are the orographically-induced vortex stretching and the surface drag related to turbulent momentum flux divergence that has an enhanced drag coefficient over land. Orographically-induced tilting/twisting can also be locally significant in the vicinity of capes. The land-sea drag difference acts as a barrier to encroachment of the wind onto the land through turbulent momentum flux divergence. It turns the wind parallel to the shore and slightly reduces it close to the coast. Another minor factor is the sharp coastal sea surface temperature front associated with upwelling. This can weaken the surface wind in the coastal strip by shallowing the marine boundary layer and decoupling it from the overlying troposphere. © 2015, Springer-Verlag Berlin Heidelberg. 资助项目: CIEE, National Science Foundation
; ONR, National Science Foundation
; NSF, National Science Foundation
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53855
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, 405 Hilgard Ave., Los Angeles, CA, United States
Recommended Citation:
Renault L.,Hall A.,McWilliams J.C.. Orographic shaping of US West Coast wind profiles during the upwelling season[J]. Climate Dynamics,2016-01-01,46(2017-01-02)