摘要
Using the daily NCEP/NCAR reanalysis dataset and the observation rainfalldata in China for the 1980-1997 period, features of severe summer rainfall over the upper reaches ofthe Yangtze River are investigated and then sources of moisture contributing to severe rainfallover eastern and western Sichuan Province (ES and WS for short) are examined with particularreference. It turns out that the severe rainfall occurring locally dominates summer rainfall overthe upper reaches of the Yangtze River. Climatological rainfall and anomalous one constitute severerainfall, but the latter accounts much for severe rainfall. The meridional moisture transportdominates the composite moisture transport on the occurrence day for ES region, while the zonal isequivalent to the meridional for WS region. Correlation between the moisture transport fluxes overthe two regions of severe rainfall and other regions, the anomaly and variation of the moisturetransport day by day during the period of severe rainfall lend a support for the conclusion that themeeting of the moisture from the West Pacific through the South China Sea (SCS) and the one fromnorthwestern China exerts a vital effect on the occurrence of severe rainfall, which can not beneglected.
Using the daily NCEP/NCAR reanalysis dataset and the observation rainfalldata in China for the 1980-1997 period, features of severe summer rainfall over the upper reaches ofthe Yangtze River are investigated and then sources of moisture contributing to severe rainfallover eastern and western Sichuan Province (ES and WS for short) are examined with particularreference. It turns out that the severe rainfall occurring locally dominates summer rainfall overthe upper reaches of the Yangtze River. Climatological rainfall and anomalous one constitute severerainfall, but the latter accounts much for severe rainfall. The meridional moisture transportdominates the composite moisture transport on the occurrence day for ES region, while the zonal isequivalent to the meridional for WS region. Correlation between the moisture transport fluxes overthe two regions of severe rainfall and other regions, the anomaly and variation of the moisturetransport day by day during the period of severe rainfall lend a support for the conclusion that themeeting of the moisture from the West Pacific through the South China Sea (SCS) and the one fromnorthwestern China exerts a vital effect on the occurrence of severe rainfall, which can not beneglected.
基金
This paper is jointly supported by the National Natural Science Foundation of China under Grant Nos. 40375014, 40475029the National Basic Research Program of China under "973" Grant No. 2004CB418300.
