近50年川中丘陵区的季节性干旱时空变化特征.doc

近50年川中丘陵区的季节性干旱时空变化特征 　　摘要：近年来川中丘陵区季节性干旱频繁发生，对四川省农业生产造成严重影响。根据川中丘陵区8个气象站点1960年―2011年的逐日气象资料，选用国家标准中相对湿润度指数作为干旱指标，采用线性趋势法、morlet小波及反距离加权插值法，研究川中丘陵区季节性干旱频率和强度的时空分布特征。研究结果表明：川中丘陵区不同季节干旱频率和强度差异大，春冬两季的干旱频率和强度显著大于夏秋两季，干旱发生主要集中在春冬两季；时间上，春旱和秋旱呈加重趋势，夏旱和冬旱呈减轻趋势，其中春旱有3个周期演变规律，冬旱有2个周期演变规律；空间上，春夏两季川中丘陵区中部为干旱高发区，秋冬两季川中丘陵区北部为干旱高发区。该研究可为川中丘陵区制定防旱减灾措施提供理论依据。 　　关键词：川中丘陵区；相对湿润指数；干旱；时空分布；小波变换 　　中图分类号：S42 文献标志码：A 文章编号2015 　　Abstract：In recent years，seasonal droughts occur frequently in the hilly area of central Sichuan，resulting in serious impacts on the agricultural production in Sichuan.According to the daily meteorological data of eight meteorological stations from 1960 to 2011 in this area，the relative humidity index in the national standards was selected as the drought index，and linear trend method，Morlet wavelet，and inverse distance weighting interpolation method were used to investigate the spatial and temporal distribution of seasonal drought frequency and intensity.The results indicated that （1） drought frequency and intensity have large differences in different seasons，and they are significantly higher in spring and winter than those in summer and autumn，and drought occurs mainly in spring and winter；（2） on the temporal distribution，drought in spring and autumn tends to be worse while drought in summer and winter alleviates.Drought in spring has three cycle evolutions while drought in winter has 2 cycle evolutions；and （3） on the spatial distribution，the central hilly area of central Sichuan has high incidence of drought in spring and summer，while the northern hilly area of central Sichuan has the high incidence of drought in autumn and winter.This study can provide a theoretical basis for the drought control and mitigation measures in the hilly area of central Sichuan. 　　Key words：hilly area of central Sichuan；relative moisture index；drought；spatial and temporal distribution；wavelet transform 　　1 研究背景 　　干旱是影响我国农业生产的主要气象限制因子之一[1]。四川省是我国重要的农业种植区，但随着