中文摘要：

通过对中国西北典型半湿润区、半干旱区、干旱区和半荒漠区4个不同气候区1951—2015年降水和气温资料的搜集、整理和处理,分析研究区1951年以来降水和气温的变化,并对其进行M-K突变检验,总结ENSO事件对气候与旱涝灾害的影响。研究结果表明：1 4个气候区降水量逐年变化幅度差异明显,半干旱区为变化幅度最小区域,半湿润区和干旱区变化幅度最大但出现降低的趋势,而半荒漠区则是降水量增长最明显的区域;降水的集中度由东往西变化逐渐增大,东部比西部滞后5 d左右。2 4个气候区气温上升幅度存在差异,半湿润区气温上升幅度最大,干旱区气温上升幅度最小。3 El Nino事件使4个气候区发生不同程度的降水减少、气温升高,而La Nina事件则使降水增加、气温降低。4 El Nino事件会给4个气候区当年带来旱灾,次年带来涝灾;La Nina事件则会给当年带来涝灾,次年带来旱灾。

英文摘要：

The variation of air temperature,precipitation and drought and flood which were affected by ENSO events in the 4 regions of northwest China was analyzed based on the data of air temperature and precipitation from1951 to 2015,and the precipitation and temperature change in the study area were tested by M-K mutation. There existed significant differences of inter-annual variation of climate between the 4 regions in the past years. The interannual variation of precipitation was in a small range in the semiarid regions,of which in the sub-humid regions and arid regions was in a wide range and decreasing trend,and the widest range was in the semi-desert regions. The temperatures of the 4 regions turned to increase constantly during 1980 s. The rate of warming was fastest in the subhumid regions and semi-desert regions. The concentration ratio of precipitation of 4 regions showed an increasing trend from east to west. And the concentration ratio of precipitation of east lagged behind 5 days the west. There existed differences of amplitude of variation of climate,the rising amplitude in the sub-humid regions was highest,and the arid regions were smallest. El Nino events contributed precipitation decreasing and temperature rising at different degree. La Nina events,otherwise,had inverse influences. El Nino events caused drought in the 4 regions of Northwest China,and caused flood in the following year,La Nina events was on the contrary.