海南航天发射场非台暴雨位涡诊断分析

Potential Vorticity Analyses on Non-typhoon Rainstorm of Hainan Satellite Launch Site

利用海南省文昌市气象站1970—2010年逐日降水资料、NCEP/NCAR全球再分析格点资料,通过湿位涡诊断分析方法,分析研究了近41年海南文昌发射场非台暴雨天气热力、动力学特征.结果表明:湿位涡能够较好地反映暴雨发生的动力、热力特征.暴雨发生时,低层湿位涡正压项MPV1<0,中高层MPV1>0,海南位于湿对流不稳定区;湿位涡斜压项MPV2的数值比MPV1小一个量级,各天气系统对应MPV2分布具有典型的上负下正特征;相对湿位涡MPVre在低层表现为一致的负值区.另外,不同天气类型暴雨的湿位涡分布特征存在显著的差异.湿位涡分布特征与暴雨系统存在较好的对应关系,湿位涡作为表征天气系统动力、热力学特征物理量之一,将为海南航天发射场暴雨预报预警提供帮助.

Using the precipitation data of Wenchang station and global reanalysis gridded data of NCEP/NCAR from 1970 to 2010, this analyzed the dynamic and thermal characteristics of the non-typhoon rainstorm. The results showed that the physical of moist potential vorticity can express the dynamic and thermal characteristics of the non-typhoon rainstorms. When the rainstorm occurs, the barotropic term of the MPV is negative in low level and positive in middle and upper. Hainan is in the area of moist convective instability. The baroclinic term of the MPV is smaller than the barotropic term. The distribution characteristics of the different weather systems shows that the MPV is negative in middle and upper and positive in low level. Relatively moist potential vorticity is negative in low level and conducive to the occurrence of convection. The moist potential vorticity is one of the physical parameters of the dynamic and thermal characteristics. It will provide assistance to the forecast and warning of the rainstorm of the Hainan satellite launch site.