The drought in South China from autumn to winter and its relationship with the circulation and ENSO

Abstract

China station precipitation data from 1951 to 2008, NCEP/NCAR reanalysis, Hadley SST and CAM3 model of NCAR are used. This paper focuses on anomalies of precipitation in South China from autumn to winter and the characters of circulation and the influence of ENSO to precipitation and circulation. The particularities of drought in South China from November 2008 to January 2009 and its climate background are studied. It shows East Asian Monsoon be stronger, the air fall down strengthen when the precipitation in South China from autumn to winter is lack. The above features are in favor of precipitation. By not only data analysis but numerical experiment, it indicate there are tight connections between the circulation of east Asian in autumn and winter, anomalies of precipitation in South China and SST in midterm and eastern tropical Pacific. Occurrence of La Nina often induces the decrease of precipitation in South China. The characteristics of circulation and SST in autumn and winter of 2008 are different obviously from those of the past years. In detail, the most significant SST anomaly locates on the western Pacific, middle tropical Pacific and middle latitude Atlantic, not on midterm and eastern tropical Pacific.