利用张家口地区14个观测站的49年（1965—2013年）降水量资料，通过计算单站旱涝指标（Z指数）、区域旱涝指数（W指数），采用线性趋势法、Mann－Kendall法（简称M－K法）对该区域进行旱涝及其变化特征分析；选取4年典型旱年与4年典型涝年的NCEP/NCAR再分析资料，对比分析其500 hPa环流形势的异同。结果表明，49年张家口地区年W指数存在弱下降趋势，年际变化幅度较大，年和季均有旱涝交替、连旱或连涝的特征。W指数出现极值的年份与降水量极值年份相对应，具有一致性，因此W指数可很好的反映张家口地区的旱涝特征。M－K突变检测分析得出，年、季旱涝突变主要发生在1968年（秋季、冬季）和1995年（年、春季、夏季、秋季）。利用NECP/NCAR再分析资料得出，旱年乌拉尔山东部到贝湖一带高压脊较强，张家口受暖脊控制；涝年贝湖低槽和我国东北冷空气活动频繁，张家口多受我国东北冷空气和贝湖低槽控制。%Based on the calculation of the flood and drought index (Z index,W index) with the precipitation data of 14 meteorological stations during 1965—2013, the variation characteristics of flood and drought in Zhangjiakou was analyzed calculated by using the linear trend method and M-K method. By se-lecting NCEP/NCAR data from four typi-cal flood and drought years, the different characteristics of 500 hPa circulating situations were analyzed. The results showed that the W index data was in the presence of a weak downward trend in the Zhangjiakou during 49 years, and ex-hibited the alternation from droughts to floods, continuous floods or droughts in the years and seasons. The extremes year of W index corresponded to the precipi-tation extremes year. These two had con-sistency and W index might well reflect the flood/drought rules of Zhangjiakou region. The results of M-K mutation test showed that W index mutation of the in-ter-annual and seasonal mainly hap-pened in 1968 and 1995. By analyzing NCEP/NCAR data, it was shown that there was a strong ridge of high pressure from the eastern Urals to the Lake Baikal area in drought years, while Zhangjiakou was controlled by a warm ridge. Once a cold air was activated frequently at Lake Baikal area or northeast China, Zhangji-akou would be controlled by a cold air in flood years.
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