By using the meteorological data from 48 weather stations during 1965 to 2014 and winter wheat growing period data in Hebei Province,selected the SPEI(standardized precipitation evapotranspiration index),taken the water requirements of winter wheat to replace the evapotranspiration in SPEI,has analyzed the drought spatial features in winter wheat growing period near 50 years,and initially discussed the causes of drought change characteristics.The results showed that:(1)Under the situation of without considering the light drought,the occur-rence frequency of medium drought was the highest as(9.2％～10.4％)in winter wheat growing period,the heavy drought was the next as(5.7％～7.4％),and the extreme drought was the lest as(1.8％～2.7％).(2)The high oc-currence frequency regions of above medium drought was located in Hengshui and Cangzhou at the early and middle growing stages of winter wheat,but the Handan was the higher occurrence frequency region at the middle and later stages.(3)The drought with high intensity and wide range was occurred during 1968～1968,1971～1972,1981～1982 and 2011 in whole wheat growing period,among them the drought was run through whole growing period in 1968,but other years were total for stage drought.(4)The drought intensity and drought range in whole growing period of winter wheat was assumed a decreasing trend at 0.01 significant level.This decreasing trend was close re-lated with the decreasing of water requirements of winter wheat,also this decreasing trend was affected by the de-crease of sunshine hours and wind speed.%利用河北省冬麦区48个气象站1965—2014年气象资料和冬小麦发育期数据,选取标准化降水蒸散指数(SPEI),以冬小麦需水量代替SPEI指数中的蒸散量,分析了河北省冬小麦生育期近50年干旱时空特征,并对干旱变化特征的成因进行了初步探讨.结果表明:(1)在不考虑轻旱的情况下,河北省冬小麦各生育期内中旱出现频率最高(9.2％～10.4％),其次是重旱(5.7％～7.4％),极端干旱出现频率最低(1.8％～2.7％).(2)冬小麦生育前、中期中旱以上干旱发生的高频率区位于衡水、沧州,邯郸则为中、后期中旱以上干旱出现的高频率区域.(3)冬小麦全生育期1966～1968年、1971～1972年、1981～1982年、2011年干旱强度较强、范围较大,是干旱较严重的年份,其中,1968年的干旱贯穿全生育期,其它年份均为阶段性干旱.(4)冬小麦全生育期干旱强度、干旱范围随年际均呈减弱趋势,且减弱趋势通过0.01水平的显著性检验;这种减弱趋势与冬小麦需水量的减少趋势关系密切,而冬小麦需水量的减小趋势又受日照时数、风速的下降趋势影响.
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