Interdecadal Variability of Spring Precipitation Over South China and Its Associated Atmospheric Water Vapor Transport
华南春季降水和水汽输送的年代际变化特征

The characteristics of spring precipitation and water vapor transport, as well as the related atmospheric circulation in South China are analyzed by using the data of observational and NCEP reanalysis data. The results show that spring precipitation in South China account for 32% of annual total, the water cycle (precipitation, wind field, water vapor transport, etc.) and the related atmospheric circulation in spring together show a notable interdecadal variability. The spring precipitation has an abrupt change in the turning point year of about 1972, which has undergone a significant increase since the early 1970s. In the period of relatively droughty years, the related atmospheric circulation is conductive to the formation of the south wind in eastern China, so there has anomalous south wind in the northern boundary of South China that make a huge outflows of water vapor, and existed a water vapor flux divergence (positive div ) in this region, causing deficient rainfall. In the period of relatively wet years, the related atmospheric circulation is conductive to the formation of the south wind in eastern China, so there has anomalous north wind in the northern boundary of South China that make a little outflows of water vapor, and existed a water vapor flux convergence (negative div ) in this region, causing sufficient rainfall.