摘要
对4种南海夏季风强度指数(1951～1998年)进行了对比分析,发现尽管它们在某些年份有差异,但在年际变化总体趋势上仍表现一致,并且由它们所确定的季风强弱年也基本相同。统计分析了南海夏季风强度与我国汛期降水的关系,结果表明,南海夏季风强(弱)年,我国夏季雨带型呈Ⅰ(Ⅲ)类分布,长江中下游地区夏季(6～7月)少雨干旱(多雨洪涝),广东省后汛期降水以偏涝(正常和偏旱)为主。南海夏季风强度指数与夏季长江中下游区降水和淮河区降水有显著的反相关,与江南区降水和华南后汛期降水有显著的正相关。我国夏季出现的严重洪涝(如1998年长江流域特大洪涝和1994年华南特大暴雨)与南海夏季风的强度异常有关。此外,分析还表明,南海夏季风活动强弱造成的北半球东亚500 hPa位势高度场的经向波列型遥相关是影响中国夏季降水的一个重要机制。
Four indexes are compared and analyzed that indicate the intensity of the South China Sea summer monsoon in 1951～1998. It is found that they are generally consistent in the interannual variation and have basically the same years of monsoon intensity as determined by them, though with some differences in some years. The relationship between the monsoon intensity and the precipitation in raining seasons in China is statistically studied and the results are as follows. In the years of strong (weak) summer monsoon in the South China Sea, the rain bands are of Pattern One (Three) distribution in the summer of China and the rainfall of the Changjiang R. Valley in June and July is mainly below and drought (above and flood), whereas rainfall is flood (normal and drought) during the yearly-second raining season in the Guangdong province. The intensity indexes for the South China Sea summer monsoon are in high anticorrelation with the precipitation over the middle and lower reaches of the Changjiang R. Valley and Huaihe R. Valley but in high correlation with that in the region south of Changjiang R. and the yearly-second raining season in southern China. Severe floods taking place in the summertime of China (like the extra severe floods in the Changjiang R. Valley in 1998 and the extra severe heavy rains in southern China in 1994) are associated with intensity anomalies of the summer monsoon in the South China Sea. In addition, meridional wave train anomalies teleconnection of the 500 hPa geopotential height field in East Asia in the Northern Hemisphere, which is resulted from the strong and weak summer monsoon activity in the South China Sea, is an important mechanism contributing to the summer precipitation in China.
出处
《热带气象学报》
CSCD
北大核心
2003年第B09期25-36,共12页
Journal of Tropical Meteorology
基金
<国家重点基础研究发展规划>G1998040900项目第一部分资助
关键词
南海夏季风强度
中国降水分布
影响机理
intensity of South China Sea summer monsoon
distribution of precipitation in China
governing mechanisms
