关键词: 宁夏, 春季降水, 水汽通量, 典型年份, 特征

Abstract: According to the precipitation data from 1961 to 2006 of the 19 main stations in Ningxia, the character of the precipitation in spring was analyzed. There were the 16-year long period and the 8-year short period, but the inter-year and the inter-decade changes were not obvious. There was a closely negative correlation between the date of first soaking rainfall and the precipitation in spring, and the possible first soaking rainfall would make great contribution to the precipitation in whole spring. Research on the water vapor transportation between 850 hPa and 700 hPa in spring-rainy year and drought year shows that there are two vapor inflow corridors to Ningxia. The one comes from the Bengal gulf and the other comes from the Caspian Sea. In the typical spring-rainy year, these two water vapor belts converge in obviously north-oriented region, with large convergence area and big central value. In the typical spring-drought year, these two water vapor belts converge in west-oriented region, with small convergence area and less central value than the normal. The water vapor flux at u direction is not different between the rainy year and the drought year, but adversely different at v direction. The Ningxia area is controlled by positive anomaly in rainy year and controlled by negative anomaly in drought year.

Key words: Ningxia, spring precipitation, water vapor flux, typical years, character