基于GPS/Pwv资料的上海地区2004年一次夏末暴雨的水汽输送分析

ANALYSES OF WATER VAPOR TRANSPORT IN A HEAVY RAIN IN THE LATE SUMMER OF 2004 IN SHANGHAI BASED ON GPS/PWV DATA

本文应用GPS探测的可降水水汽资料Pwv对上海地区2004年一次夏末暴雨的水汽输送特征进行了分析。结果表明:此次暴雨过程的水汽输送路径有两条,一条是西南水汽输送路径,一条是东南水汽输送路径。指出边界层的偏东急流是此次暴雨过程的主要增雨机制。分析还表明:每30 min一次的GPS/Pwv资料能直观地、及时地反映大气中水汽的时间变化和空间变化;GPS/Pwv资料随时间的演变特征与降水有较好的对应关系;GPS/Pwv的散度资料可以反映大气中水汽的辐合、辐散分布情况。

With the use of Precipitable Water Vapor （PWV） data from GPS, analyses were performed to study the features of water vapor transport in a heavy rain case that occurred during the late summer of 2004 in Shanghai. Results indicated that two paths of water vapor transport existed in the case; one is southwestwardly path in the synoptic-scale, the other is southeastwardly path in the meso-scale. Easterly jet stream in the boundary layer was a main mechanism of increasing rainfall. It is shown that GPS/PWV data with an time interval of 30 minutes reflected spatial and temporal changes of atmospheric vapor intuitionally and duly, the features of GPS/PWV changes had corresponding relations with the precipitation, the divergence of GPS/PWV showed the distributions of the convergence and divergence of atmospheric vapor.