【摘要】 根据1961—2000年河北省69个站逐月降水资料,采用Z指数作为各代表站旱涝等级划分标准,根据计算出的Z指数把旱涝情况划分成7个等级,并在此基础上计算了河北省历年干旱的严重程度和干旱发生的范围。对近40年来的资料分析表明:这一区域冬季干旱面积变化不大,春、秋季干旱面积呈减小的趋势,夏季干旱面积呈扩大趋势,年干旱面积也呈扩大趋势。更多还原

【Abstract】 Monthly rainfall of 69 meteorological observation stations in Hebei Province during 1961-2000 are used for calculating Z-indices which are divided into 7 grades to scale the severity of dryness and wetness of each station.The regional drought index is also proposed to investigate the change of severity and coverage of droughts of the entire area.The results show that the drought coverages are different in different seasons: The drought area shrinks in spring and autumn,and expands in summer,and shows no obvious change in winter.The annual drought area shows expanding trend.更多还原