4种干旱指标在河西走廊地区的适用性评估

Applicability Assessment of Four Drought Indexes in Hexi Corridor Regions

为了对比4种干旱指标在河西走廊地区的适用性,利用中国气象局提供的河西地区12个气象站点1960—2013年地面观测数据,计算出该区4种干旱指标,并对照《中国气象灾害大典》的实况干旱记录资料,评估这4种干旱指标在河西走廊地区的适用性。结果显示:(1)在年际尺度上,Pa和MI所判定的干旱等级高于实测干旱等级,SPI和SPEI的模拟能力相对较好;在季节尺度上,SPEI的判断结果与实际情况更为接近;(2)Pa、SPI和MI在整个河西走廊的部分区域均呈现不同程度的变湿趋势,而SPEI的倾向率空间分布特征表明河西走廊地区以不同的速率变干;(3)Pa、SPI和SPEI的干旱频率一致;MI在降水更加稀少的干旱区域适应性和可靠性相对较差;(4)SPEI与MI的相关性在干旱的疏勒河流域较差;(5)通过与实际干旱记录的对比,发现4种指标的出现错误的频率为MI>SPI和Pa>SPEI。

In order to assess the applicability of four kinds of drought indexes in Hexi Corridor regions, theindexes were calculated with the data of 12 meteorological sites in Chinese Meteorological Administration inHexi Corridor from 1960 to 2013, and the applicability was assessed according to The Chinese Meteorological Disasters Encyclopedia. The results showed that：（1） on the annual scale, the drought grades assessed by Pa and MI were higher than the observation data, the simulating ability of SPI and SPEI was relatively good; onthe seasonal scale, the judgment result of SPEI was more close to the actual situation;（2） wetting tendency haddifferent degrees in some regions assessed by Pa, SPI and MI, but drying tendency showed in Hexi Corridorassessed by SPEI;（3） Pa, SPI and SPEI had the same drought frequency; the adaptability and reliability of MI were relatively poorer in drought area;（4） the correlation between the SPEI and MI in the arid Shule river basinwas relatively poor;（5） compared with the actual drought records, the error rates of the four indexes followedthe order of MI〉SPI and Pa〉SPEI.