Abstract: In this paper, the variation of air temperature, precipitation and drought and flood disasters which were affected by ENSO events in the Hexi Corridor was analyzed based on the data of air temperature and precipitation in Dunhuang, Jiuquan, Zhangye and Wuwei cities in the Hexi Corridor in recent 58 years. The results showed that the annual air temperature in the corridor was in an increase trend in fluctuation way, and its increase rate was 0.3 ℃/10 a; annual precipitation was slightly increased, and its increase rate was 2.3 mm/10 a. The occurring frequency of regional drought and flood disasters in recent 58 years was 50%. The wavelet analysis revealed that there were the 4-5year periodicity of slight flood and drought disasters, 13-14year periodicity of moderate ones, 18-19year periodicity of serious ones, and 26-27year periodicity of extremely serious ones. The effect of ENSO events on mean annual air temperature was more significant than that on mean annual precipitation, air temperature in the El Nino years was obviously increased, and the precipitation was slightly increased; in the La Nina years, the air temperature was distinctly decreased, and the mean annual precipitation was increased by 10.5 mm. There was a significant correlation between the ENSO events and the regional drought and flood disasters, the regional drought and flood disasters occurred mainly around the years of ENSO events, especially in the years of successional ENSO events.

Key words: ENSO event, air temperature, precipitation, drought and flood disaster, disaster periodicity, Hexi Corridor