SVD ANALYSIS BETWEEN THE MOISTURE FLUX AND PRECIPITATION IN "0801 SNOW STORM OVER SOUTHERN CHINA"

Using the daily wind field,specific humidity,surface air pressure data of NCEP/NCAR and daily precipitation data of 194 stations in China for the period of January 10 to February 2,2008,characteristics of moisture flux field in "0801 snow storm over southern china" are analyzed.It is shown that there exists a high value area of the vertically integrated moisture transport and its divergence in southern China.By means of singular value decomposition(SVD) method,the relationship between the anomaly field of moisture transport flux and rainfall anomalies is investigated.And two pairs of coupled modes with statistical significance and distinct synoptic meteorological significance are revealed.Among them,the first modes with the variance contribution rate of 81.50% and the correlation coefficient for its time coefficient of 0.80 describe that when the southwest winds moisture transport anomalies from the Bay of Bengal and South China Sea strengthen,but also converge in the junction of Sichuan,Yunnan,Guizhou and areas of Guangdong,Fujian,Jiangxi in China,it is rainy in most parts of the south of the Yangtze River.The second modes with the variance contribution rate of 8.80% and the correlation coefficient for its time coefficient of 0.64 indicate that when the moisture transport anomalies from the western Pacific Ocean enhance in eastern Chinese mainland and converge along the Guangxi-Zhejiang region,it is rainy in the middle and lower Yangtze River Basin,but rainless in Guangxi,Guangdong and Fujian.