摘要
采用二维和三维完全弹性参数化冷云数值模式模拟研究了低层单向切变风场中积云的发展演变过程和地面降水特征。结果表明:在低层切变风场中,用热泡扰动方式激发对流的启动条件提高,而冷出流方式激发对流则更加容易。适当强度的低层切变使对流峰值强度减小,但积云生命史延长,地面累计总降水量增大,雨区拓宽,峰值雨强则减小。采用二维模式来模拟单向切变风场的对流活动虽然存在严重歪曲,但积云最大升速以及地面总降水随时间的演变特征与三维模拟结果一致。
The two—and three—dimensional versions of a fully elastic numerical cloud model with icephase microphysics parameterization are used to investigate the evolution and surface precipitationfeatures of convective clouds in unidirectional low—level wind shear fields.The simulations showthat,in order to trigger a convection in low level wind shear environment by thermal bubble,amore intensive temperature disturbance is needed,whereas it can be initiated much easier by coldoutflow.Low—level shears with certain intensity lead the peak intensity of convections to de-crease,but result in a longer lifetime,larger amount of cumulative surface precipitation,and moreextended rainfall area with some smaller peak rainfall rate.Although the two—dimensional simu-lations of convective activities in vertical shear environment have some severe distortions,theevolution features of maximum updraft velocities and total surface precipitation are coincidentwith the results of the three—dimensional simulations.
出处
《应用气象学报》
CSCD
北大核心
1992年第1期21-31,共11页
Journal of Applied Meteorological Science
基金
LASG 部分资助
