1960—2014年广东省干旱时空演变特征

利用1960—2014年广东省24个气象站点的逐日降水资料,采用下次降水平均等待时间（Average Waiting Time for Precipitation, AWTP）计算得到的相当干期（Equivalent Dry Period, EDP）指数分析了广东省1960—2014年的干旱时空特性,重点分析其自21世纪以来的干旱时空演变趋势。结果表明：EDP指数能够较好地适用于本研究区。从空间分布上看,广东省干旱大致呈现自西向东、自北向南逐渐加重的空间分布格局,东南部沿海地区干旱程度较粤北和粤西地区更为严重。1960—2014年广东省干旱有明显的年代际的变化特征,且干旱程度存在显著的逐年加重趋势。此外,广东省存在典型的季节性干旱,秋旱和冬旱频发,其次是春旱;各季的干旱中心位置有所不同。21世纪以来广东省干旱的发生频率、强度和影响面积都远超20世纪后半叶。具体而言,进入21世纪,珠三角东部东源站和粤西云浮市罗定站的EDP值明显增高,成为广东省新的干旱中心。从季节性干旱的角度分析,21世纪以来,秋季与冬季的旱情加剧最为严重并向全省蔓延,秋、冬季EDP值在21世纪初期相对20世纪后半叶的增幅都为23%。春旱则是逐年缓慢加重,夏旱在1960—2014年较少,但进入21世纪后广东省夏旱也呈现频发的态势。

Spatio-Temporal Variation of Drought in Guangdong Province from 1960 to 2014

Drought has a serious impact on socio-economic development in China and around the world.This study used daily precipitation records from 24 meteorological stations in Guangdong Province,China from 1960 to 2014 to analyze the spatio-temporal characteristics of drought in that region based on the Equivalent Dry Period(EDP)metric converted from the Average Waiting Time for Precipitation index.Particular emphasis was placed on the spatio-temporal evolution of drought in the 21^st century.The results showed that the EDP index was suitable for analyzing drought characteristics in Guangdong Province.Overall,drought intensity decreased from east to west and from south to north,with coastal areas experiencing more severe drought than northern and western areas.During the study period,decadal variations and an annual increasing trend in EDP were obvious over the entire province.In addition,seasonal drought was prominent,occurring most frequently in autumn and winter,followed by spring;the drought's central location varied from season to season.Drought frequency,intensity,and spatial extent were all higher in the early 21^st century than those in the late 20th century.Specifically,since the turn of the century,both Dongyuan Station in the eastern Pearl River Delta and Luoding Station in western Guangdong showed significant increases in EDP and emerged as new drought hotspots.From a seasonal perspective,autumn and winter drought intensified most severely and tended to extend throughout Guangdong Province,with an EDP increase of 23%from the late 20th century to the early 21^st century.Spring drought worsened more gradually and summer drought occurred more frequently(though still rarely)in the early 21^st century.These results identified the spatial pattern and temporal evolution of drought in Guangdong Province since the turn of the century and provide scientific references and technical support for drought monitoring and mitigation in southeastern China.