IMPACTS OF THE LOW FREQUENCY OSCILLATION IN EAST ASIAN SUMMER MONSOON ON THE DROUGHT AND FLOODING IN THE MIDDLE AND LOWER VALLEY OF THE YANGTZE RIVER

The relation between the low frequency oscillation in East Asian summer monsoon and the drought and flooding in the middle and lower valley of the Yangtze River is studied in this paper. Our study shows that the low frequency oscillation of 30～60d is the most remarkable in the strong summer monsoon surge years in the South China Sea and easily causes the flooding in the middle and lower valley of the Yangtze River. On the contrary, in the weak summer monsoon surge years in the Southern China Sea, the low frequency oscillation of 10～20d is more active than that of 30～60d and easily causes the drought. The propagation of monsoon surge low frequency oscillation is important to the precipitation’s medium and long range prediction in the middle and lower valley of Yangtze River.