Precipitation variation over southeastern China in winter and its circulation pattern

Based on the precipitation data at 160 stations in China and the NCEP/NCAR reanalysis data during 1951—2011,this paper studies the interannual variability of winter precipitation over southeastern China and associated circulation and water vapor transport characteristics.Results show that interannual variation of winter precipitation over southeastern China is significant.When the precipitation anomaly is positive(negative),the sea level pressure anomalies are negative (positive) of Mongolian high and over southern China,and positive(negative) in the adjacent sea area of Asia;At 500 hPa,the high pressure ridge near the Balkhash Lake and East Asia trough both are weaker(stronger);westerly jet of Eastern Asia is weaker(stronger),and westerly jet of the Middle East is stronger(weaker).There is a significant abnormal ascending(sinking) motion over 20—30°N eastern China and an abnormal sinking(ascending) motion in low latitudes.Two dominating water vapor transports affect winter precipitation over southeastern China.Firstly,a water vapor transport comes from the south branch airflow of the westerlies around the Tibetan Plateau,by Arabian Sea and the Bay of Bengal,to South China.Secondly,a water vapor transport comes from the low-latitude western Pacific,by South China Sea,to Southwest China.In addition,there is a negative correlation between East Asian winter monsoon index and winter precipitation over southeastern China.