河西走廊降水及其干旱特征研究

Spatiotemporal changes of precipitation and drought in Hexi Corridor

根据河西走廊20个气象台站1971～2006年降水资料,基于Z指数干旱指标,应用EOF数理统计方法深入探讨4～9月、4月、5～6月3个关键期的干旱特征。研究表明:河西走廊降水普遍减少,但降水变化具有差异性。干旱特征高度一致,中西部对干旱变化响应敏感。3个关键期的旱灾区域分别集中在西部、中东部(尤其是张掖)、东西两端,并在1991、1999、2001形成重灾年。90年代以来干旱范围显著增大,干旱强度明显增强。因此,区域农业应采取因地制宜、区别对待的发展策略。

Using Z-index and empirical orthogonal function（EOF） method,three key periods,Apr.-Sept.,Apr.,May-June,were studied on the basis of the precipitation data provided by 20 meteorological stations from 1971 to 2006 in Hexi Corridor.The results showed that there was a general decline in precipitation,with a difference in its changes.Drought had a high degree of consistency,the response to drought was very sensitive in the central and western regions.In three key periods,the droughts mainly occurred at the west,central and eastern（especially Zhangye）,east and west.Severe droughts occurred in 1991,1999,2001.The range of drought significantly increased,the intensity of drought markedly enhanced.Therefore,the regional agriculture should be taken to local conditions,different treatment strategies for development.