The Characteristics and Cause Analysis of Guangdong Abnormal Torrential Rain in the Background of Late Autumn Severe Drought in 2009

In the background of late autumn severe drought, a torrential rain happened in Guangdong province from 11th to 13th, November 2009.The precipitation center was located on the severe drought region, northern Guangdong and Pearl River Delta.By analyzing the circulation situation, it is revealed that the east movement of westerly trough at high latitude led strong cool air down to the south.The interactions between cold and warm air mass produced the torrential rain.Moreover, the quantity diagnosis and numerical simulation show that the convergence of water vapor, which releases latent heat, also played an important role in the maintenance of the heavy rain.