Roll Vortices in the Boundary Layer Caused by a Concave Wind Profile: A Theoretical Study  

作　　者：LIU Hui-Zhi SANG Jian-Guo 

机构地区：[1]State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry （LAPC）, Institute of Atmospherie Physics, Chinese Academy of Sciences, Beijing 100029, China [2]Physies School, Peking University, Beijing 100871, China

出　　处：《Atmospheric and Oceanic Science Letters》2010年第6期308-311,共4页大气和海洋科学快报（英文版）

基　　金：supported by the National Basic Research Program of China (973 Program) (Grant No. 2010CB951801);the National Natural Science Foundation of China (Key Program) (Grant No. 41030106)

摘　　要：The present study solves a two-layer atmospheric wave equation model with a lower atmosphere concave wind profile and cold-air outbreak over sea, while simultaneously proving that such a wind shear may cause neutral boundary layer roll vortices in the presence of disturbing sources upstream. Without thermal effects, the wind shear-induced waves have band structures at the top of the boundary layer that are similar to cloud street patterns observed over sea. This study proves that dynamic and thermal effects can act independently to initiate the roll vortices in the lower atmosphere. At the same time, a quantitative comparison shows that dynamic effects play a large role in the formation of roll vortices in the initial stage of cold-air outbreak and will be surpassed by thermal effects soon after surface heating commences.The present study solves a two-layer atmospheric wave equation model with a lower atmosphere concave wind profile and cold-air outbreak over sea, while simultaneously proving that such a wind shear may cause neutral boundary layer roll vortices in the pres- ence of disturbing sources upstream. Without thermal effects, the wind shear-induced waves have band structures at the top of the boundary layer that are similar to cloud street patterns observed over sea. This study proves that dynamic and thermal effects can act independently to initiate the roll vortices in the lower atmosphere. At the same time, a quantitative comparison shows that dynamic effects play a large role in the formation of roll vortices in the initial stage of cold-air outbreak and will be surpassed by thermal effects soon after surface heating commences.

关 键 词：roll vortex concave wind profile Ekman laver wind shear cold advection 

分 类 号：P404[天文地球—大气科学及气象学] O357.4[理学—流体力学]