2007年淮河流域强降水过程的水汽输送特征分析

A Diagnostic Study of Water Vapor Transport and Budget during Heavy Precipitation over the Huaihe River Basin in 2007

利用NCEP再分析资料,引入基于拉格朗日方法的气流轨迹模式（HYSPLITv4.9）,将2007年6月19日~7月26日期间淮河流域强降雨分为三个阶段,分析不同阶段水汽输送轨迹、主要通道及其不同源地的水汽贡献。结果表明,影响此次强降水过程的水汽通道主要有三支：一支是西太平洋上副高边缘东南气流输送,另一支是南海南部越赤道气流的北向输送,第三支是沿索马里急流经阿拉伯海和孟加拉湾北部的水汽输送。降水第一阶段来自西太平洋洋面的水汽输送最强,占总水汽输送的69%,降水后两个阶段南海南部越赤道气流的水汽输送占优势,分别占总水汽输送的52%和57%。另外,通过轨迹分析可知本次降水过程中索马里至孟加拉湾通道的水汽输送到淮河流域上空750 hPa以上大气,南海及西太平洋的水汽主要输送到淮河流域850 hPa以下的低层大气。

By using the NCAR/NCEP reanalysis data and the HYSPLITv4.9 mode,the variation features of the water vapor transportation and the contribution of vapor for major passages are analyzed during the heavy precipitation over the Huaihe River basin from 19 June to 26 July in 2007 which is divided into three stages.The results show that there are three major vapor inflow corridors to the Huaihe River basin.One of them is the southeast flow around the western Pacific subtropical high,another is northward vapor transport from cross-equatorial flow in the southern South China Sea,the last is from Somali jet via the Arabian Sea and the northern Bay of Bengal.During the first stage,the transportation of vapor originating from the western Pacific is most important and accounts for 69% of the total transportation.During the second and third stages,the cross-equatorial flow in the southern South China Sea is dominant and accounts for 52% and 57% of total moisture transportation,respectively.Somali jet via the Bay of Bengal transports moisture to the levels above 750 hPa,and the South China Sea and the subtropical high moisture transports to the levels under 850hPa.