锡林浩特地区夏季极端气候特征分析

Analysis of Extreme Climete Characteristics in Summer in Xibinhot

以内蒙古锡林浩特1970—2015年夏季极端气候变化为研究对象,采用了6个极端气候指数(持续干燥指数(CDD)、持续湿润指数(CWD)、日最大降水量(Rx1day)、5 d最大降水量(Rx5day)、暖昼日数(TX90p)、高温日数(SU35))和标准化降水蒸散指数(SPEI)进行分析,以期了解该区极端气候变化特征,为内蒙古典型草原生态发展提供参考依据。结果表明:6月连续无雨和有雨日间隔在缩小;暴雨和强降水有增加的趋势;SPEI有增加的趋势,该月有变湿润的趋势。7—8月,连续无雨日间隔在增大而有雨日间隔在缩小;暴雨和强降水有减小的趋势;SPEI有减小的趋势,该月份有变干旱的趋势。6—8月极端高温均有增加趋势。在干旱程度和极端气候指数相关性分析中,SPEI与Rx1day、Rx5day的相关性最大,暴雨和强降雨可能有效缓解旱情发生。在相同月份,极端气候指数在不同旱情下表现是不同的。

Taking the summer extreme climate change in Xilinhot,Inner Mongolia from 1970 to 2015 as the research object,six extreme climate indexes(CDD,CWD,Rx1 day,Rx5 day,TX90 p and SU35) and standardized precipitation evapotranspiration index(SPEI) were analyzed in order to understand the characteristics of extreme climate change in the region and provide a theoretical basis for the ecological development of the region.The results showed that the interval between continuous rain free days and rainy days was shrinking,rainstorm and heavy rainfall were increasing,SPEI was increasing,which showed that June had a trend of becoming humid.From July to August,the continuous non rainy day interval was increasing while the rainy day interval was shrinking.The rainstorm and heavy rainfall had a decreasing trend,and SPEI had a decreasing trend,indicated that July to August had a trend of becoming dry.From June to August,the extreme high temperature increased.In the correlation analysis of drought degree and extreme climate index,SPEI had the greatest correlation with Rx1 day and Rx5 day,and rainstorm and heavy rainfall might effectively alleviate drought.In the same month,the performance of extreme climate index was different under different drought conditions.This study provided a reference for the change of extreme climate in the typical steppe area,and was of great significance for the protection of ecosystem in Inner Mongolia.