近60 a来内蒙古极端降水时空变化及其影响

基于内蒙古地区41个气象站点1958-2017年的逐日降水数据,采用世界气象组织等推荐的9个极端降水指数,运用线性趋势分析、克里金插值法、Mann-Kendall检验、Morlet小波分析和主成分分析等方法研究了内蒙古地区近60a来极端降水时空变化、周期规律和气象灾害效应。结果表明:内蒙古地区近60a来出现了干燥化趋势,即伴随着降水量的减少,各极端降水指数出现不同程度的下降趋势,以20世纪60年代和21世纪初下降最为明显。各极端降水指数倾向率在空间上大体呈现出从东西部向中部递减的规律,大都以集宁、呼和浩特、通辽和新巴尔虎右旗为低值中心。各极端降水指数的最大概率突变年为1995年,此后出现了不显著下降的趋势。各极端降水指数均存在3~5 a、14~17 a、20 a左右的周期变化。除连续无雨日数外,各极端降水指数与年降水量之间均存在较好的相关性。内蒙古极端降水变化导致该区旱灾与风灾增多加重,草原沙漠化加强,洪灾与低温冻害减少减轻,应有针对性地采取措施加强旱灾与风灾预防。

Spatiotemporal Variation and Effect of Extreme Precipitation in Inner Mongolia in Recent 60 Years

This study was based on the daily precipitation data from 41 meteorological stations in Inner Mongolia from 1958 to 2017. The 9 extreme precipitation indices suggested by WMO,liner trend method,Kriging interpolation,Mann-Kendall test,Morlet wavelet analysis and principle component analysis were used to study the spatiotemporal and periodic changes of extreme precipitation and its disasters in Inner Mongolia. The results showed that a drying trend occurred in Inner Mongolia in recent 60 years,especially in the 1960s and the beginning of this century.Spatially,the extreme precipitation indices were holistically in a decrease trend from the eastern and western parts to the central area,and their low values occurred in Jining,Huhhot,Tongliao and Xin Barag Right Banner. A mutation of the extreme precipitation indices occurred in 1995,and after that these indices were in a slight reduction. There were the 3-5 a,14-17 a and about 20 a periodic changes of extreme precipitation indices. There were the high correlations between the extreme precipitation indices and the annual precipitation except CDD. The change of extreme precipitation in Inner Mongolia resulted in the drought and wind disasters,grassland desertification and reduction of flood and low temperature disasters in the study area. Suitable measures should be taken to prevent and control drought and wind disasters.