ENSO事件对河西走廊气候与气候灾害的影响

通过对河西走廊敦煌、酒泉、张掖、武威4个城市58 a来气温和降水资料的搜集和整理，分析该区域气温和降水的变化、ENSO事件对该区气候以及旱涝灾害的影响。结果表明：1952年以来，该区年均气温总体呈波动上升趋势，气温增长率约0.3 ℃/10 a；年均降水量略有增加，增长率约2.3 mm/10 a。在58 a内该区发生旱涝灾害的频率为50%。小波分析显示，该区域轻度旱涝灾害周期为4~5 a，中度旱涝灾害周期为13~14 a，大的旱涝灾害周期为18~19 a，重的旱涝灾害周期为26~27 a。ENSO事件对该区平均气温的影响比平均降水量的影响明显，厄尔尼诺年气温明显升高，降水量略有增加；拉尼娜年气温明显降低，但年均降水量增加了10.5 mm。ENSO事件与该区旱涝灾害关系显著，该区域的旱灾和涝灾主要发生在ENSO事件年或前后年，并且旱涝灾害多发生在连续性的ENSO事件年。

Effect of ENSO Events on Climate and Climatic Disasters in the Hexi Corridor,Gansu Province

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.