临近寒潮相互影响关系及高层位涡的预报作用

Interaction between the approaching cold waves and the prediction of high potential vorticity

利用ERA-Interm 1°×1°逐6 h再分析资料,对2017年1—2月发生的两次寒潮事件(简称过程A和过程B)的天气环流形势和位势涡度进行对比分析。结果表明:(1)过程A爆发后的冷空气促进过程B的形成;(2)等熵面上的位势涡度可用来追踪并判断寒潮的变化特征;(3)通过350~200 hPa处的位涡值特征可提前6 h预测寒潮开始爆发的时间和强度;(4)上游和下游系统对判断寒潮爆发的特征同样有着重要作用。

Based on the 6 h reanalysis data of ERA-Interm 1°×1°,the synoptic circulation situation and potential vorticity of two cold wave events(process A and process B for short)from January to February 2017 were comparatively analyzed.Results show that:(1)the cold air after the explosion of process A promotes the formation of process B.(2)The potential vorticity on isentropic surface can be used to track and judge the variation characteristics of cold wave.(3)Based on the potential vorticity characteristics at 350-200 hPa,the time and intensity of the onset of cold wave can be predicted six hours in advance.(4)The upstream and downstream systems play an equally important role in determining the characteristics of cold wave outbreaks.