Abstract:

In this paper，the precipitation anomaly percentage，K integrated meteorological drought index and the Ci drought index were
used to analyze the rare drought event lasting from summer and autumn of 2009 to winter and spring of 2010 in Anshun of Guizhou
Province． The results show that three kinds of drought indexes had a certain significant instruction for the drought period，drought development，
drought easing and removing phase，and this severe drought event was involved with meteorology，hydrology，agriculture，social
and economic aspects． The descriptions of the drought trend by three indexes were basically same． The K index could best reflect
both actual agriculture drought status in winter and spring and hydrology drought in most of time，the Ci index could reflect the agricultural
drought in most parts of the region． Drought in summer and autumn was assessed much severe by the K index，but considering the
effect of evaporation，it could reflect the lack of moisture，the judgment about drought removing completely by the K index was more accurate．
While the precipitation anomaly percentage was not so stable，especially in low rainfall period，the determine of the ending time
was not good enough． The assessment of the monthly and seasonal drought showed that K index was the best in winter ( the most serious
drought time) ，Ci and the precipitation anomaly percentage were good for the drought in summer and autumn．

Key words: drought assessment, K index, Ci index, the precipitation anomaly percentage

摘要：

采用降水距平百分率、K 干旱指数和综合气象干旱指数( Ci) ，通过3 种指数各自的干旱等级划分，对2009 年夏秋季到2010 年冬春季发生在贵州省安顺市的历史罕见的干旱过程进行了评估比较。结果表明: 3 种干旱指数对此次历史罕见的干旱灾害的干旱时段，干旱发展、缓解、解除阶段均有一定的指示意义。此次干旱过程是一次涉及气象、水文、农业、社会经济方面的综合性特大干旱过程。3 种指数对干旱发展趋势的描述基本一致。K 指数最能体现冬春季农业和大部分时段水文干旱的实况，Ci 指数可体现大部分地区农业干旱的实际。K 干旱指数对夏秋季旱情评估偏重，但由于其考虑了蒸发，对水文上水分的欠缺有一定的反映，对干旱彻底解除的时间判定较为合理。降水距平百分率则不够稳定，特别是在降水基数少的时段，对干旱结束时间判定较差。对月和季干旱的评定，冬季干旱最严重的时段K 指数评定最好，Ci 和降水距平百分率则对夏秋季干旱评定较为合适。

关键词: 干旱评估, K 干旱指数, Ci 指数, 降水距平百分率