位涡和Q矢量诊断在毛乌素沙地沙尘天气预报中的应用

Application of Potential Vortex and Q Vector in Dust Storm Weather Forecasting in Mu Us Desert

利用常规的天气图、卫星云图、湿位涡和Q矢量等,对2007年4月30日和2007年5月2日发生在毛乌素沙地的两次沙尘天气进行了综合分析。结果表明:对流层低层MPV1<0中尺度对流不稳定区的生成,为干对流的发生提供了不稳定能量条件;来自上游对流层中高层的干侵入和扰动干侵入在沙尘天气发生过程中起着重要作用;对流层低层由Q矢量辐散、辐合激发生成的次级环流为沙尘天气发生、发展和维持提供了动力机制。在对毛乌素沙地中β尺度沙尘暴的预报预警过程中,同时应考虑下沉对流有效位能的作用。

Based on the routine synoptic chart, satellite nephogram, wet potential vortex and Q vector and some other data, comprehensive analysis for the two cases of dust storms happened on April 30, 2007 and May 2, 2007 respectively over Mu Us Desert are presented in the paper. The results show： the generation of mesoscale convection instability in the low troposphere with MPV1 〈 0 provides the instability energy for the generation of the dry convection; the dry intrusion and turbulence intrusion which come from the upstream area in the middle and high layers of troposphere play a very important role in the formation of the dust storm weather; sub-circulation triggered by the divergence and convergence of Q vector in the low troposphere provides the dynamic mechanism for the generation, development and maintenance of the dust storm weather. The effect of downward convection capable potential energy should be considered in the β scale dust storm forecasting and warning in Mu Us Desert.