一次东亚寒潮过程的等熵位涡分析

ANALYSIS WITH ISENTROPIC POTENTIAL VORTICITY ON A COLD WAVE IN SOUTHEASTERN ASIA

本文用等熵位涡(IPV)图分析了1983年1月3—8日东亚寒潮过程的动力学特征。在寒潮酝酿阶段,IPV 平流过程(特别是东北急流的作用),东北急流与其南面西偏北气流构成的东西向切变线与 IPV 极大值线相配合,以及西偏北气流沿等熵面的绝热上升冷却,这三者对于对流层中层横槽形成、加强和南下,以及中层冷堆和地面冷高压的加强起着重要作用。我们认为,用 IPV 图分析大尺度天气过程的动力学性质比较实用,是一种有很大潜力的分析和预报工具。

The dynamical characteristics of a cold wave in southeastern Asia during 3—8 January1983 were analysed with isentropic potential vorticity(IPV)charts.In the brewing stage of thecold wave there are following three factors that play important role for the formation,intensifica-tion and southward movement of transversal trough in the mid-troposphere,and for the enhance-ment of mid-troposphere cold dome and surface cold high.They are IPV advective process(spe-cially northeastern jet),coincidence of the shear line between northeastern jet and northwesterlywith IPV maximum line,and cooling process of upward northwestern flow.We believe IPVcharts to be really effective for dynamic analysis of large scale weather process,and they areshown to be a useful tool for weather analysis and forecasting.