淮河流域旱涝年水汽输送特征分析

基于1951~2007年6~8月逐日NCEP/NCAR再分析资料，计算了淮河流域夏季旱涝年的整层水汽输送通量及散度，以揭示旱涝年相对于正常年的异常水汽输送特征。结果表明，淮河流域洪涝年与干旱年的异常水汽输送通量及散度场均呈反相位变化，洪涝年降水的偏多得益于西南水汽输送的增强和向北输出水汽的减弱及整层水汽输送通量散度辐合，而干旱年降水的偏少是西南水汽输送减弱、大量异常水汽向北输出及整层水汽输送通量辐散共同作用的结果。

Characteristics of Water Vapor Transportation in Huaihe River Basin in Drought and Flood Years

Based on the NCEP/NCAR (National Centers for Environmental Prediction/ National Centers for Atmospheric Research) daily reanalysis data in June ~ August from 1951 to 2007, the vapor transportation flux and divergence are calculated when drought and flood occurred in Huaihe River Basin in summer. And then the abnormal characteristics of water vapor transportation between flood/drought years and normal years are analyzed. The results show that the distribution of vapor transportation flux and divergence in flood years is opposite in drought years; precipitation is abundant in Huaihe River Basin in flood years could be ascribed to an increase of vapor current from southwest and the whole layer vapor convergence, while a decrease of the vapor flux transporting to the north; however, in dry years, large scales of abnormal vapor transports to the north and the southwest vapor current as well as the whole layer vapor convergence become weaker, which contribute to the decrease of precipitation over the Huaihe River Basin.