2008年1月我国低温雨雪冰冻气象灾害中的水汽输送特征

本文利用NCEP/NCAR逐日再分析资料对2008年初我国低温雨雪冰冻极端气象灾害中的水汽输送特征进行了分析,结果表明:在灾害集中发生的1月份,高原南侧、孟加拉湾北部的偏西风水汽输送和来源于西太平洋副高南侧的偏东风水汽输送为我国南方地区源源不断地输送水汽;和气候平均状态相比,1月份来自孟加拉湾、西太平洋、南海地区的异常偏南风水汽输送尤为强盛;此外还具体分析了4次天气过程的水汽输送、辐合形势以及偏南风水汽输送的扩展特征,发现第3次过程中国东部大陆尤其是华南、江南一带上空的水汽输送最强,来源于南半球的水汽也参与了第3次过程;每1次天气过程的发生发展均对应出现偏南风水汽输送大值区。

Water Vapor Transport Analysis of the Severe Cold Surge,Ice-snow and Frozen Disasters in China during January 2008

During January 2008,a severe cold surge,ice-snow and frozen disasters occurred in China.The disasters,which led to huge losses in the country,are unprecedented because of their national-wide influences,their infrequent intensity,and long time lasting periods of the low temperature,snowstorm,and frost days.In this article,based on NCEP/NCAR reanalysis data,water vapor transport analysis of the disasters are studied.It is found that the water vapor in the disasters is mainly from the Bay of Bengle,the South China Sea and the west Pacific ocean.Compared to the climate average,the anomalous water transport from the Bay of Bengle,South China Sea and the west Pacific Ocean in January is abnormally stronger.During the process of the disasters,the atmospheric precipitation water over the Pacific ocean obviously moves westwards strengthening to the South China Sea and then advances northward to the southern regions of the China;the progress and retreat of the atmospheric precipitation water are corresponding to the beginning and ending of each weather process.The water transport features in the four weather processes are also analyzed in this paper.The results show that,among the four weather processes,the water transport intensity of the third is the strongest and it is worth mentioning that the water transport from southern hemisphere contributes to it;the beginning and ending of the weather process are corresponding to the appearance and disappearance of the strong water vapor transport center.