2009年7月广西一次暴雨过程的数值模拟和诊断分析

NUMERICAL SIMULATION AND DIAGNOSITC ANALYSIS OF A JULY 2009 RAINSTORM PROCESS IN GUANGXI PROVINCE

运用WRF模式对2009年7月发生在广西地区的一次暴雨过程进行了数值模拟,并利用模拟结果进行诊断分析。结果表明,模式能够合理地再现此次暴雨天气过程。在对流层中低层,水汽通量散度的负高值区、假相当位温广义波作用量密度和z-螺旋度的正高值区,与强降水落区都存在较好的对应关系;水汽通量散度负值中心大小及负值区向上伸展的高度、假相当位温广义波作用量密度的高值中心值,与降水强度之间存在一定的相关性;z-螺旋度的强度变化对降水强度的增大和减弱也具有较好的指示意义。

The WRF model is used to simulate a case of rainstorm occurred in Guangxi province in July 2009,the results of model output are used to diagnostic analysis.It is indicated that in mid-lower troposphere the high value areas of negative moist flux divergence,positive wave-activity density of pseudo-equivalent potential temperature and positive z-helicity have good correlations with the location of heavy rain.The negative value and extension height of moist flux divergence,and the value of wave-activity density of pseudo-equivalent potential temperature have some correlations with the intensity of precipitation.The variation of z-helicity intensity is also a valuable indicator of the intensity of heavy rain.