中文摘要：

为了掌握内蒙古极端气候事件的发生趋势与时空格局，本文运用内蒙古自治区境内46个国家级气象站点的日值记录数据，计算与植被生长的水热条件及寒旱灾害直接相关的极端气候事件指数，分析过去50年内蒙古温度和降水气候事件的时空演变特征。研究结果表明，研究区极端温度事件的发生频率与持续时间迅速变化发生于20世纪90年代以来，60年代至80年代末呈平稳态势。表征低温事件的霜日日数（FD0）、冷昼日数（TX10p）、冷夜日数（TN10p）、冷持续指数（CSDI）等指数均呈现下降趋势，同时表征高温事件的夏日指数（SU25）、作物生长期（GSL）、暖昼日数（TX90p）、暖夜日数（TN90p）、热持续指数（WSDI）则均呈上升趋势。与极端高温事件发生频率的加剧在90年代初开始凸显不同，表征强降水事件发生频率和强度的极端降水指标的显著变化发生在近10年。研究区极端温度指数过去50年的变化过程几乎没有明显的空间分异特征，但是在位于农牧交错区的部分站点的强降水事件呈现出与大多数站点不同的特征，最近10年的强降水事件高于前一时段，而其他多数站点最近10年的极端降水指数均低于前一时段。

英文摘要：

Frequently occurrences of extreme climatic events in recent years have become a focus of sustainability research, because they threaten the ecosystem balance and even the sustainable development of social-ecological system. In this study, by the daily record data of 46 national meteorological stations in Inner Mongolia during the past 50 years, 15 indexes that characterize the frequency and probability of extreme climatic events are calculated with RclimDex （1.0）. The trends and spatial pattern of extreme climatic events across this region were obtained. The results indicate that frost day （FD0）, the percentile value of cold night （TN10p）, the percentile value of cold day （TX10p） and the duration of coldness （CSDI） that characterize the extremely low temperature presented downward trends; meanwhile, summer day （SU25）, crop growth period （GSL）, the percentile value of warm night, the percentile value of warm day （TX90p） and the duration of warmness （WSDI） that characterize the extremely high temperature showed upward trends. Since the 1990s, the frequency and duration of extreme temperature events increased fast in comparison with the smooth trends from the 1960s to the late 1980s. Different from extreme temperature events, obvious extreme precipitation events variation started since the latest 10 years, heavy precipitation and 5-daily maximum precipitation were both much lower than those in the preceding 40 years. Extreme temperature indexes in 46 sites in the study area almost had the same variation process and there was no clear spatial differentiation. However, at some sites located in the farming-pastoral ecozone, heavy precipitation events occurred more frequently in recent 10 years than in the preceding 40 years, while the heavy precipitation events in recent 10 years occured less frequently than in the preceding periods at the other sites.