ESVD ANALYSES OF THE ANOMALY OF SEA SURFACE TEMPERATURE AND THE PRECIPITATION IN MAY OVER LOW-LATITUDE PLATEAU OF CHINA

Making use of reanalysis data provided by ECMWF,sea surface temperature data provided by NOAA,and precipitation data over low-latitude plateaus of China in May,we analyzed the relationship between the precipitation over the low-latitude plateaus in May,vapor flux with its divergence and the global SST anomaly(SSTA)by using extended singular value decomposition(ESVD).The results of statistical diagnosis and numerical simulation show that there is significant correlation between the precipitation over the plateaus and vapor flux with its divergence in May and the SSTA from January to May.A conceptual climate model for the SSTA influence on the precipitation of this region in May can be proposed as follows.When the tropical SSTA presents a tripole mode of "-,+,-" from the Indian Ocean to the eastern Pacific or the negative phase of ENSO"Modoki" pattern,more water vapor is transported to the plateaus form the Bay of Bengal,exposing them to a vapor flux convergence anomaly area and eventually leading to increased precipitation over the plateaus in May.When SSTA is distributed in modes opposite to that above,the precipitation decreases in May.Because of the persistent nature of SSTA from January to May,its pattern is a key factor and a strong influence signal for the precipitation,which can be used for short-term climatic forecast.