衡水市1961～2015年极端降水和干旱的时空变化特征

Spatial and Temporal Characteristics of Extreme Precipitation and Drought in Hengshui City from 1961 to 2015

基于河北省衡水市11个气象站点1961～2015年逐日降水数据,采用StarDex极端降水指数和SPEI干旱指数对全市开展极端降水和干旱时空变化规律研究。结果表明:(1)最大连续无雨日(PXCDD)与平均干旱期长度(PDSAV)随时间呈上升趋势,而最大连续有雨日(PXCWD)和年降水量则下降。(2)从空间分布来看,极端降水指数反映西部和北部的干旱化趋势较明显。(3)SPEI指数变化表明,1990年代后干旱次数增加,夏、冬季和年序列均有向干旱发展的趋向;西部和北部发生干旱的频率较高。(4)极端降水指数和SPEI指数存在较好的相关性;SPI和SPEI在12个月尺度上有较好的一致性,但在对干旱程度的判定上有偏差;不同等级的干旱年份中,极端降水指数和SPI指数也有较好的表现。总的来看,衡水市干旱渐趋严重,且呈夏、冬两季多发,西部和北部受灾严重的特征,应在水资源规划与管理中做好水资源配置。

Based on the daily precipitation data of 11 meteorological stations in Hengshui City,Hebei Province from 1961 to 2015,StarDex extreme precipitation index and SPEI drought index were used to analyze the spatial and temporal characteristics of precipitation and drought in the city.The results showed that:(1)the Max no.consecutive dry days(PXCDD)and the mean of dry spell lengths(PDSAV)show an upward trend,while Max no.consecutive wet days(PXCWD)and annual precipitation decreased.(2)From the perspective of spatial distribution,there was a trend toward drought in the western and northern regions.(3)SPEI indicated a significant increase in the occurrence number of drought after the 1990 s.Annual,summer and winter series tend to develop toward drought.Droughts occured more frequently in the west and north.(4)The extreme precipitation index correlated well with SPEI.SPI and SPEI had good consistency at the 12-month scale,but there were differences on the degree of drought.The extreme precipitation index and SPI performed well in typical drought years of different degrees.In general,the drought in Hengshui City was becoming more and more severe,which was characterized by frequent occurrence in summer and winter,and severe disaster in the west and north.