多种干旱监测指标在黄河流域应用的比较

利用黄河流域(包括青海、甘肃、宁夏、陕西、山西、河南、山东、内蒙古中西部)145个气象站1961—2010年月降水、气温、蒸发资料,为探讨目前国内常用的干旱监测指标的区域适用性,对比分析了几种干旱监测指数在黄河流域的应用情况,这些指数包括综合气象干旱指数(CI)、标准化降水指数(SPI)、帕默尔干旱指数(PDSI)、降水距平百分率(Pa)和K干旱指数(K)。结果表明,近50 a来,5种干旱指数中,K和CI对干旱的监测结果与实际情况吻合得较好,其次分别为SPI、Pa和PDSI。就CI和K而言,CI监测结果过于偏轻,对研究区内一些较重的干旱过程有遗漏;K对干旱程度的判断在某些区域(如青海、内蒙古中西部)过于偏重,对河南的夏、秋季干旱过程有遗漏。总体来说,在黄河流域,K指数监测的干旱结果与实况最为吻合,使用K的监测结果能最接近地反映实际的干旱状况,但以下情况除外,对于河南的夏、秋季,内蒙古的冬季,建议采用CI的监测结果;内蒙古的夏季,K和CI的监测结果均比较适宜,可结合使用;山东的冬季,K和Pa的监测结果可结合使用;山东的夏季,建议采用Pa的监测结果;而对于青海省,各个季节均建议使用SPI的监测结果。

Comparison among Several Drought Indices in the Yellow River Valley

In order to realize the applicability of common drought indices, the application situation of several drought indices in the Yellow River Valley is analyzed by using monthly precipitation, temperature and evaporation data of 145 stations in the valley from 1961 to 2010. These indices include comprehensive index (CI) of meteorological drought, standardized precipitation index (SPI), Palmer drought severity index (PDSI), precipitation anomaly percent (Pa) and K drought index. The results show that K drought index and CI of meteorological drought can get the best monitoring effect for the real drought for the past 50 years when making comparisons among these five drought indices, then followed by SPI, Pa and PDSI. When comparing CI with K drought index, we found that CI can monitor drought with a weaker effect to the real drought, so it could leave out some heavy drought processes in the research area, and K drought index can monitor drought with a heavier effect for some regions such as Qinghai, middle and west Inner Mongolia, at the same time, it could leave out some heavy drought processes in summer and autumn in Henan. In summary, K drought index has the best monitoring effect in the Yellow River Valley, the monitoring effect of K drought index can best reflect the conditions of real drought except for using it in summer and autumn of Henan and winter of Inner Mongolia, for under such conditions it was suggested to use CI; the monitoring effect of K drought index and CI both fit well for summer in Inner Mongolia, so these two indices can be combined to monitor drought in this region; K and Pa can be used together to monitor drought in winter of Shandong, but Pa is suitable for drought monitoring in summer of Shandong; and it is suggested to use SPI for all seasons in Qinghai.