近40年内蒙古暴雨日数气候特征及趋势

利用内蒙古自治区119个台站1971-2008年近40年的逐日降水资料,通过趋势分析、功率谱分析、小波分析、Mann-Kendall突变检验等方法,分析内蒙古自治区暴雨日数气候特征。结果表明：内蒙古暴雨日数的空间分布具有从东南向西北递减分布,暴雨日数最多出现在7月中、下旬和8月上旬;暴雨量日数存在10年的主周期,此外还存在3年的次周期;暴雨日数在1998年前后存在一次突变,1999-2008年年均暴雨日数比1971-1998年年均值减少了17.1d。

Climatic Characteristic and Trend of Rainstorm Days in Inner Mongolia in Recent 40 Years

Based on the daily rainfall data from 119 meteorological stations in Inner Mongolia region from 1971 to 2008, the climatic characteristic of rainstorm days was demonstrated by trend analysis, power spectrum analysis, wavelet analysis and mann-kendall test. A spatial distribution characteristic that the number of rainstorm days decreasing from southeast to northwest in the Inner Mongolia was observed and rainstorm days with higher amount of rainfall were found to frequently appear around the middle of July, the end of July and the beginning of August. There was the main period of 10 years and the secondary period of about 3 years of the rainstorm days. A mutation of the rainstorm days around the year of 1998 was encountered, and the average rainstorm days from 1979 to 2008 is 17.1 day shorter than that from 1971 to 1998.