倾斜涡度发展与β中尺度低涡  

Slantwise Vorticity Development and Meso-β Scale Low Vortex

作　　者：姜勇强[1] 陈中一[1] 周祖刚[1] 朱相富[1] 

机构地区：[1]解放军理工大学气象学院,江苏南京211101

出　　处：《解放军理工大学学报（自然科学版）》2004年第6期81-87,共7页Journal of PLA University of Science and Technology(Natural Science Edition)

摘　　要：利用中尺度暴雨模式MRM1,对1998年7月21、22日湖北黄石的β中尺度低涡及特大暴雨进行数值模拟,采用湿位涡守恒原理对模式输出的高时空分辨率物理量场进行分析。结果表明,β中尺度低涡是在低层θe水平梯度加大,θe等值线变得更加倾斜、近似陡立而发生SVD的情况下产生的。pm1在本次特大暴雨过程中是主要的,大大超过pm2,低层对流稳定度绝对值的迅速减小造成垂直涡度的急剧增大,从而形成β中尺度低涡。因此,θe等值线变得陡立可能是气旋性涡度激烈发展导致对流性特大暴雨形成的一个重要原因。Numerical simulation is made for extremely heavy rain and meso-β scale low vortex in Huangshi of Hubei province during 21-22 July 1998 using a meso scale rainstorm model MRM1. High spatial and temporal resolution model-output physical fields are analyzed according to the conservation principle of moist potential vorticity. The meso-β scale low vortex occurred under the condition of occurring slantwise vorticity development(SVD) which is due to the increasing horizontal gradient of low-level θ_eand more slant near steep θ_eisotaches. The analyses using the conservation principle of moist potential vorticity show that p_(m_1)is principal and it exceeds p_(m_2)greatly. The vertical vorticity increases rapidly because of the rapidly decreasing of absolute value of low-level conditional instability, and then meso-β scale low vortex forms. So θ_ethe steep change of isotaches must be an important reason for the formation of convective extremely heavy rain due to rapid development of cyclonic vorticity.

关 键 词：Β中尺度低涡 倾斜涡度发展 湿位涡 数值模拟 

分 类 号：P456.7[天文地球—大气科学及气象学] P435