Probability distribution of precipitation extremes during raining seasons in South China.

Based on the daily precipitation data at 71 stations in South China and the NCEP/NCAR reanalysis monthly mean SLP (Sea Level Pressure) data in the Southern Hemisphere during 1960-2005, the probability distribution of precipitation extremes during the rainy seasons (April-June and July-September) in South China was investigated by using statistical methods, such as the Le Page test and the GEV (General Extreme Value) analysis, The influences of the Australian High and the Mascarene High in the southern Hemisphere on the heavy precipitation days of the south china were also examined. The results show that an abrupt change of precipitation trend in South China occurred around 1992, from a descendent trend to an ascending trend. After the abrupt change, precipitation extremes and the daily maximum precipitation both weakened reduced in the first rainy season (April-June) but significantly enhanced in the second rainy season (July-September). The spatial distribution of precipitation extremes in every fifty years exhibited a similar pattern to that of the daily maximum precipitation and the heavy precipitation days, i.e, in the first rainy season it showed “negative-positive-negative”from south to north and in the second rainy season it became “positive-negative”. After 1992，the spatial distribution of the daily maximum precipitation variation were agreed with that of the heavy precipitation days. On the interdecadal time scale, when the Australian High and the Mascarene High were stronger, precipitation extremes would be less than normal in the first rainy season and more than normal in the second rainy season.