HLAFS资料在短期降水、气温MOS预报方法中的应用

通过对HLAFS资料建立的5~9月夏半年气温、降水方程中所选的因子进行统计整理,找出使用频率最高的因子。气温方程中所选的因子,24 h气温预报方程中以24 h前的因子多;而48 h预报方程中多选24 h后的因子,实况因子选中的几率大,与预报员的思路一致。降水方程中,因子辐散风选中的最多,其次为Q矢量散度和涡度。利用“1999.7.4”庆阳大到暴雨个例,对方程中使用最多因子的实时场和预报场进行了分析,所选因子有较明确的物理意义,为以后MOS预报降水因子的选取提供了参考依据。

Application of HLAFS Information in MOS Forecast for Precipitation and Temperature

The chosen factors in the temperature and precipitation equations established using HLAFS information in May to September are concluded in order to find out the factors used most frequently.Results show that factors chosen in the temperature forecasting equation for 24 hours are mainly before 24 hours,while in that for 48 hours,the factors are mainly after 24 hours,and the factors in real time are chosen in large probability,which is consistent with forecaster's;in precipitation forecasting equations,the first chosen factor is the divergence wind,and then the divergence and vorticity of Q vector.The heavy storm case in Qingyang on 4 July 1999 was used to analyze the real time and forecasting fields using most factors in forecasting equation,and the chosen factors have clear physical meaning,which provides reference basis for selecting precipitation factors in MOS forecast.