湖南省基于scPDSI指数的干旱时空特征分析

Analysis on Spatial and Temporal Characteristics of Drought in Hunan Province Based on scPDSI Index

本文基于高空间分辨率的改进帕默尔干旱指数(sc PDSI),采用Mann-Kendall非参数突变检验法、经验正交函数分析法(EOF)对湖南省干旱时空特征进行分析。结果表明,(1)1961—2009年,湖南省发生干旱的频率为8.2%;(2)整体上,湖南省年际、春季、秋季变湿趋势显著,且均以1988年为突变点,但是在进入2000年代后进入相对干旱的时期;夏季呈现由干变湿的显著趋势,并在1990年发生突变;冬季呈现显著变干趋势,并在2004年发生突变;(3)整体来看,湖南省处于正常状态,其中湘西北小面积处于轻微湿润,湘中小面积和湘西南小面积处于轻微干旱状态;(4)利用经验正交函数得到的前4个EOF空间模态,将湖南省划分为4个干湿特征区域,分别为湘南地区、湘西北地区、湘东北地区和湘中地区,其中湘东北和湘中地区变湿趋势显著,湘南和湘西北区域变干趋势显著。

Based on the newly published self-calibrating Palmer drought severity index（sc PDSI）data with high spatial resolution,the MannKendall nonparametric test and the empirical orthogonal function analysis（ EOF） were adopted to investigate the spatial and temporal variation characteristics of the drought in Hunan Province in this paper.The results showed that the frequency of drought in Hunan Province was 8.2% from 1961 to 2009.Hunan Province became moist significantly from 1961 to 2009 in annual,spring and autumn as a whole,and 1988 was the mutation point.But after 2000 s,it was in a period of a relatively dry.Meanwhile,Hunan Province became moist significantly at summer scale with the mutations detected at1990,winter became drought significantly scale with the mutations detected at 2004.Hunan Province was in a normal state as a whole,in which the small area of northwestern Hunan was slightly moist,small area in central Hunan and small area in southwestern Hunan were slightly dry.According to EOF,Hunan Province was divided into 4 regions with different characteristics of drought or wetness,namely South Hunan,Northwest Hunan,Northeast Hunan and Central Hunan.Among the 4 regions,Northwest Hunan and Central Hunan had significant trends to get moist;South Hunan and Northeast Hunan had significant trends to get dry.