江苏省雨日及降水量的气候变化研究

利用江苏省1960—2000年13个测站逐日降水资料,分析了41 a来江苏省年、季、月雨日的时空特征和雨日的气候变化。结果表明,江苏省的年雨日已经明显减少,平均每10 a雨日减少10.4 d。各季的雨日都呈负趋势,平均每10 a季雨日减少2.6 d。而秋季雨日减少最明显也最多。雨日长期趋势变化有明显的空间变化。江苏省的年雨日东部比西部减少的多,东部雨日每10 a减少14.6 d。月雨日也呈减少趋势,尤以4月、9月明显。雨日的长期趋势变化与降水量的长期趋势变化并不完全一致,这种不一致表现在长期趋势变化的强度上、范围上。总的来说,雨日的负趋势变化要强于降水量,负趋势的范围也要比降水量来得广一些。

CLIMATE VARIATION OF RAINFALL AND WET DAYS IN JIANGSU

Climatic change of wet days and the spatial/temporal features of annual,seasonal,and monthly wet days in Jiangsu province are investigated in the context of the observational data at 13 stations in the period of 1960-2000.It is pointed out that the annual wet days has declined at a mean rate of 10,that is,4 days per decade.The temporal trends of seasonal wet days are all negative.While the reduction of autumn wet days is the largest in magnitude,therefore,it is most remarkable.As far as the spatial change of the secular trend variation of annual wet days be concerned,the reduction of annual wet days is larger in east of Jiangsu province than in west of Jiangsu province,where the reduction rate is 14.6 days per decade.The long-term trend of monthly wet days is reduced,especially in April and September.The secular trend variation of wet days does not completely accord with that of rainfall and the intensity of negative trend and its scale display this point.In general,negative trend of wet days is larger than that of rainfall.The negative trend of annual wet days covers a larger area than the negative trend of rainfall does.