THE INTERANNUAL AND DECADAL VARIABILITY OF PRECIPITATION FOR YUNNAN PROVINCE IN RAINY SEASON AND ITSRELATIONSHIP WITH TROPICAL UPPER LAYER TEAT CONTENT

Based on the monthly precipitation data of 126 observation stations from 1961 to 2000 in Yunnan Province, the interannual and decadal variability of precipitation in rainy seasons are studied by using wavelet analysis. It is shown that there is a 2-6 year oscillation at the interannual time scales and a quasi-30 year oscillation at the decadal time scales. These periodic oscillations relate to the distribution of tropical heat content. When the precipitation is much more (less) than normal, the upper seawater is colder (warmer) in almost all the tropical Indian Ocean, and warmer (colder) in the western Pacific as well as colder (warmer) in the eastern Pacific. The key areas of the anomaly heat content distribution that have significant correlation to the Yunnan precipitation in rainy season are in the southern hemispheric Indian Ocean with a dipole pattern in the winter as well as in the deep basin of the South China Sea (SCS) before the Yunnan rainy season begins. Therefore, the anomalous distributions of the heat content in the southern Indian Ocean and the SCS In winter are good indicators for predicting drought or flood in Yunnan Province in the following rainy season.