暴雨落区的诊断预报方法

Diagnostic Forecast Method of Rainstorm area

通过对 1995～ 1998年 6～ 8月暴雨过程的样本提取 ,获得有大雨以上站点的样本记录 6 39个。选取能够反映暴雨发生的 9个物理量 (T -Td、水汽通量散度、锋生函数、假相当位温、涡度、散度、垂直速度、Q矢量涡度、Q矢量散度等 )共 16个要素值 ,用相对独立的方法 ,分别提取黑龙江省南部和北部 6、7、8月暴雨发生时各要素的临界值 ,从而建立暴雨的诊断预报模型。另外 ,用该模型对 1995～1998年 6～ 8月的降水过程进行了检验 ,并对 1999年 6～ 8月的降水进行了试报 ,结果表明该方法具有较高的使用价值。

Through the study of precipitation events in June,July and August from 1995 to 1998,this paper acquires 639sample records with precipitation amount above 25 ,which occurred at the stations in the province.We selected 9 thermodynamic and dynamical factors,which reflect spaial structure of rainstorm,including T-Td,moisture flux divergence,frontogenesis function,pseudo-equivalent potential temperature,vorticity,divergence,vertical volecity,Q vector vorticity and Q vector divergence.By using a relatively independent method,critical values of those factors were determined at the time of rainstorm happening in south and north regions and a rainstorm diagnosis forecasting model was built.In addition,with this model,we forecasted precipitation of June,July and August of 5years from 1995 to 1999.The result is affirmative and shows that this model is valuable for forecasting rainstorm.