湖南降水变化及与印度降水关系研究

基于湖南和印度的降水资料,采用回归分析、相关系数和小波分析方法研究了近46 a来湖南降水变化趋势、湖南与印度降水关系以及湖南年降水的周期。结果表明:(1)湖南年降水微弱增加,存在4个特征时间尺度,分别为3 a左右、7 a、11 a以及22 a左右。同时发现年降水以22 a左右尺度上的周期振荡为主。(2)湖南冬夏降水显著增加,春秋降水微弱减少。值得注意的是夏季降水增加而降水日数却在减少,这导致了暴雨发生概率的加大。(3)湖南与印度降水关系较好。如同期,湖南与印度东北区降水关系最为密切,自春到冬,两者相关程度逐渐加大。降水的上述变化趋势致使湖南洪涝、旱灾和暴雨事件频发,严重影响着人们的生产与生活。

Precipitation Change in Hunan and Its Relationship to That in India

By using the method of linear regressive and wavelet analyses,the trends of precipitation change,the correlation of precipitation between Hunan and India and the periodicity of annual precipitation in Hunan are studied with the data from 89 meteorological stations in Hunan during the period of 1960-2005 and those from India Meteorological Department in India during the period of 1871-2004.It is found that the in Hunan in the past 46 years had a slight rising trend with 4 periods,namely 3-year,7-year,11-year and 22-year,especially the 22-year period.The precipitation in summer and winter increased obviously in Hunan,and decreased slightly in spring and autumn.The probability of heavy storm increased,as the rainfall amount increased but the number of precipitation days decreased in summer.There was close relationship for precipitation between Hunan and India,especially between Hunan and northeast India,and the correlative degree increased gradually from spring to winter.The precipitation change brought disadvantageous effects on Hunan,leading to continual disasters of floods,droughts and heavy storms that make bad impacts on the production and life of the local residents.