Numerical Simulation of Roll Vortices in the Convective Boundary Layer  

作　　者：刘辉志 桑建国 

机构地区：[1]The State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences [2]Physics School,Peking University

出　　处：《Advances in Atmospheric Sciences》2011年第3期477-482,共6页大气科学进展（英文版）

基　　金：supported by the key project of Chinese Academy of Sciences(KZCX2- YW-219);the National Basic Research Program of China(973 Program,2010CB951801).

摘　　要：Roll vortices,which often appear when cold air outbreaks over warm ocean surfaces,are an important system for energy and substance exchange between the land surface and atmosphere.Numerical simulations were carried out in the study to simulate roll vortices in the convective boundary layer(CBL).The results indicate,that with proper atmospheric conditions,such as thermal instability in the CBL,stable stratification in the overlying layer and suitable wind shear,and a temperature jump between the two layers in a two-layer atmosphere,convective bands appear after adding initial pulses in the atmosphere.The simulated flow and temperature fields presented convective bands in the horizontal and roll vortices in the crosswind section. The structure of the roll vortices were similar to those observed in the cloud streets,as well as those from analytical solutions.Simulations also showed the influence of depth and instability strength of the CBL, as well as the stratification above the top of the CBL,on the orientation spacing and strength of the roll vortices.The fluxes caused by the convective rolls were also investigated,and should perhaps be taken into account when explaining the surface energy closure gap in the CBL.Roll vortices,which often appear when cold air outbreaks over warm ocean surfaces,are an important system for energy and substance exchange between the land surface and atmosphere.Numerical simulations were carried out in the study to simulate roll vortices in the convective boundary layer（CBL）.The results indicate,that with proper atmospheric conditions,such as thermal instability in the CBL,stable stratification in the overlying layer and suitable wind shear,and a temperature jump between the two layers in a two-layer atmosphere,convective bands appear after adding initial pulses in the atmosphere.The simulated flow and temperature fields presented convective bands in the horizontal and roll vortices in the crosswind section. The structure of the roll vortices were similar to those observed in the cloud streets,as well as those from analytical solutions.Simulations also showed the influence of depth and instability strength of the CBL, as well as the stratification above the top of the CBL,on the orientation spacing and strength of the roll vortices.The fluxes caused by the convective rolls were also investigated,and should perhaps be taken into account when explaining the surface energy closure gap in the CBL.

关 键 词：convective bands convection-wave interaction FLUXES 

分 类 号：P433[天文地球—大气科学及气象学]