“8.28”过程的多普勒雷达回波与水汽输送特征分析

The Characterrstic of Doppler Radar Echo and Vapor Flux in "8.28" Rainstorm

利用多普勒天气雷达资料及NCEP\NCAR逐日每6h再分析资料,对甘肃省2003年8月27～28日的连续性大到暴雨过程(简称"8.28"过程)进行了分析。结果表明:多普勒零速度线在测站两侧顺转程度不一致,是暖平流和大尺度辐合运动的叠加所造成的,这一结构为强降水的产生和维持提供了有利的水汽垂直输送和辐合上升运动;逆风区、中小尺度的辐合辐散都与强降水之间存在着密切的关系,是临近降水预报的重要指标;降水的区域和量级与水汽通量输送的大小及其辐合程度有关。

Using the data of Dopplor radar and reanalysis data of NECP/NCAR, the rainstorm process which occurred on August 27,28 in 2003 in Gansu province was analyzed in this paper. The results show that the reason of veer degree of zero speed line differing from one side to the other side of the station was the big scale confluence adding on the warm advection, the structure offered advantageous vertical vapor transportation and confluence rising for producing and maintaining strong precipitation; upwind section and middle-small scale confluence ( divergence) were in close connection with strong precipitation and that is an important index on precipitation prediction; the region and amount of precipitation have connection with the amount of vapor flux transportation and the degree of vapor confluence.