中文摘要：

干旱是影响我国的主要气象灾害之一,本文采用标准化降水指数SPI作为干旱评价因子对近50年来河北省干旱的时空变化特征进行了研究,得出以下主要结论：（1）春季干旱最为严重,干旱率呈逐渐降低的趋势,夏季干旱率呈逐渐增加、秋季和冬季干旱率略有降低的趋势;（2）春季干旱在20世纪70年代最为严重,夏季、秋季和冬季的年代际干旱分别以2000年以来、20世纪60年代和90年代最为严重;（3）春季干旱发生概率均大于20%,发生概率大于30%的旱情多发地区在各市均有分布;全省大部分地区夏季、秋季和冬季干旱发生概率为20%～30%,夏季干旱多发地区主要集中在河北省北部和西南部,秋季干旱多发地区主要集中在河北省西部和南部,冬季干旱多发地区主要集中在河北省北部。

英文摘要：

In the context of global warming and human activities,drought has become one of the most serious meteorological disasters in the world.As a major grain producing province in China,Hebei Province shows great vulnerability to drought.In this paper,standardized precipitation index（SPI） was used as drought indicator and precipitation in meteorological stations of China from 1958 to 2007 was used to calculate the index in spring,summer,autumn and winter.Kriging interpolation was applied to SPI values in each station so that all the values could be spatially and temporally comparable.Based on raster data of seasonal SPI,drought rate and drought probability were calculated to show the spatial and temporal distribution characteristics of drought in Hebei Province over the past 50 years.The results showed that spring drought was the most serious event in a year and the drought rate showed a gradually declining trend.Drought rate in summer presented an upward trend,but in autumn and winter it showed slightly declining trends.The 50-year average drought rates in spring,summer,autumn and winter were 30.0%,26.0%,27.6% and 26.0%,respectively.Over the past 50 years in Hebei Province,spring drought in the 1970s was the most severe one.The most serious interdecadal droughts occurred respectively in summer since 2000,autumn in the 1960s and winter in the 1990s.Occurrence probability of spring drought was more than 20% in the whole province and drought-prone areas with the probability more than 30% were almost distributed in each city.In most areas,occurrence probability of summer drought,autumn drought and winter drought was from 20% to 30%.In summer,drought-prone areas were mainly located in the north and southwest of Hebei.Drought-prone areas in autumn were mainly located in the western and southern parts and in winter they were mainly distributed in the northern part.In order to do a good job in drought prevention and mitigation in Hebei Province,government and agricultural managers should pay more attention to the droughts