强降水落区中单站降水诊断分析和预报

对2003年7月19日湖北省发生的一场降水强度较强、落区面积较大但武汉市单站出现暴雨空报的大到暴雨过程进行分析。通过诊断分析，解释了其区域暴雨发生和单站暴雨空报原因。结果表明，这是一次典型的中纬度斜压系统引起的大尺度大到暴雨过程，它的发生机制可用准地转运动理论给予很好的解释。而单站的强降水，特别是大到暴雨区中或大到暴雨区边缘单站的大到暴雨是否发生，必须通过诊断分析次级环流，当次级环流条件满足时，才能产生暴雨，否则会出现空报现象。

Diagnostic Analysis and Single-Station Area Forecast of a Strong Precipitation Event

In order to improve the single-station precipitation forecast accuracy, a case study was conducted on a strong precipitation event on 19 July 2003 in Hubei Province. Through diagnostic analysis, the causes of circulation formation were discussed. The results show that it was a typical large-scale heavy rain process resulted from a mid-latitude barocline system, and its formation mechanism can be explained by the quasi-geostrophic theory. For strong precipitation forecast, especially severe heavy rainfall forecasts within or at the edge of the raining area, secondary circulation must be diagnosed and analyzed. Only when the conditions of the secondary circulation are met, heavy rainfall will occur; or else there will be an absent forecast.