1959—2003年青海省干湿变化分析

Dryness/Wetness Changes in Qinghai Province During 1959-2003

利用青海省1959—2003年气象资料,计算了修正的Palmer干旱指数,并对其进行了分析。结果表明:在青海省旱涝监测中,PDSI指数反映旱涝程度更为客观;青海省的干旱主要以轻旱为主;夏秋季年际干湿交替较冬春季频繁,变化振幅也较大;秋季青海省干旱化倾向最为严重,冬春季出现轻旱几率最大。另外,春季干旱总面积在减小;夏季轻旱面积增加,而中旱、重旱面积在减小;秋冬季重旱面积在增加。

Based on analyses of the meteorological data at 29 meteorological stations in Qinghai Province from 1959 to 2003, the corrected Palmer drought severity index （PDSI） was calculated and analyzed. The results show that the PDSI is more objective in comparison with Z index in dryness/wetness monitoring. Most of droughts were light in Qinghai, the interannual alternations of dryness/wetness in summer and autumn were more frequent with larger change ranges in comparison with winter and spring. The drought trend in autumn was the severest, and the probability of light drought was the largest in winter and spring. Moreover, the total drought area in Qinghai Province decreased in spring, the light drought area increased in summer, but the medium and heavy drought area decreased, and the severe drought area increased in winter and autumn during 1959-2003.