关键词: 降水量, 大气环境, 年际变化, 年代及变化

Abstract: Using the monthly rainfall data from 2419 weather stations with 0.5°×0.5° resolution and the NCAR/ NCEP reanalysis data from 1958 to 2007 in the Eastern China, the variations of winter rainfall and the corresponding circulation were analyzed. The results indicate that there is a climatic trend for rainfall in the recent 50 years. The water vapor resource is more abundant in 1990s, while it is contrary in 1960s and 1970s, which could reveal the intensity of water vapor transport in the East Asia and how much water vapor is transported from ocean to island in China. The difference between years of abundant and scarcity rainfall could reach 40 mm. The correlation coefficient between rainfall and water vapor budget is 0.605. The regression coefficient between water budget and rainfall suggests that the anomalous large value is located in the south of the Yangtze River basin. Winter wind is weak for the years with abundant rainfall; it is the abnormal circulation with cyclone type in lower and upper troposphere; the abnormal southward wind prevails in the low level; the abnormal warm and wet water vapor from the Bay of Bengal and the South China Sea is transported into the eastern China. The sea surface temperature is high in the eastern China and the vertical ascending action strengths, which is favorable to the increase of water vapor, so rainfall increases.

Key words: Rainfall, Atmospheric circulation, Inter-annual variability, Inter-decadal variability