江苏地表湿润状况的变化趋势与区域特征分析

Variation Trend of Surface Humid Index and Regional Characteristics in Jiangsu Province

为了了解江苏省地表湿润状况,利用江苏省60个气象站1961—2005年月降水和月平均气温资料,通过构造一个既包含降水变化又考虑温度变化对潜在蒸发影响的干湿指标—地表湿润指数Hi=P/Pe(P为观测的月降水总量,Pe为月最大潜在蒸发),采用M-K法,对比分析了江苏省区域平均地表湿润指数的年代际变化特征及季节性差异,并讨论了它与降水和气温的联系,突出了在全球变暖背景下温度变化对干湿变化的重要影响。最后给出了地表湿润指数各季节变化趋势的地理分布。结果表明:苏北和苏南地区的年际变化趋势基本相反。由于温度的升高苏北苏中地区均出现变干趋势,苏南部分地区降水显著增加却没有呈现显著变湿趋势。江苏地区的干化趋势主要发生在春秋季节。

In order to realize the situation of the surface humid in Jiangsu province, a dry-wet index, including the impact of both surface air temperature and precipitation on the potential evaporation, is established by using monthly mean temperature and monthly precipitation data of 60 meteorological stations in Jiangsu province from 1961- 2005. The index is defined as Hi= P/Pc （P is the monthly total of precipitation, Pe is the potential evaporation from air temperature）. Analysis of the index by Mann-Kendall method, the inter-annual variation, decadal variation and the sea- sonal differences of the surface humid index, precipitation and temperature over Jiangsu province are analyzed. The warming impact on the surface dryness/wetness state is studied. The geographical distribution and trend of surface humid index are given in the areas. The results indicate that the inter - annual variation of surface humid index over northern Jiangsu is contrary to that of the south region of Jiangsu. There exists a relationship between the drying trend and the warming impact in north and middle part of Jiangsu province. The obvious wetting trend doesn＇t occur in the regions where the precipitation increases in some part of south Jiatagsu. Also, the results show that the drying trend of Jiangsu province generally occurred in spring and autumn.