城市化对北京市极端气候的影响研究

The effect of urbanization on extreme climate events in Beijing

利用北京地区20个气象站点35年(1980—2014年)的逐日降水、气温资料和社会经济、人口、土地覆被以及夜间灯光遥感的栅格数据,通过聚类分析和层次分析相结合的方法将站点分类,对北京市城市化进程中的极端气候变化趋势和城市化影响的响应进行了分析。结果表明:北京市整体的极端冷事件呈减少趋势,极端暖事件呈增加趋势,极端降水事件没有明显变化趋势;城市化对极端温度事件有着显著的影响,相对于乡村站点来说,城市化使得极端冷事件减少的更快,极端暖事件增加的更快,造成城市的气温日较差明显变小;城市化对极端降水的影响虽不显著,但在乡村站点年降水量总量和降水日数减小的趋势下,城市化造成城市降水总量和降水日数均多于乡村,减缓了连续无降水日数的增长趋势,同时城市的极端降水有向更加极端的情景发展。

It had been proved that the process of urbanization had an effect on extreme weather events under the global warming.This study analyzed the urbanization effects on extreme climate events for the period 1980-2014 by classifying 20 meteorological stations into urban,suburban,and rural categories,based on the daily precipitation,temperature data and raster data of socio-economic,population,land cover and the night-time light images combined with cluster analysis and analytic hierarchy methods.The results show that the number of extreme cold events in Beijing showed decreasing trends,while that of the extreme warm events exhibited increasing trends,and the extreme precipitation events showed no obvious change trend.Compared with rural sites,urbanization has a significant impact on extreme temperature events.In urban areas,the number of extreme cold events was reduced faster;that of extreme warm events increased faster;and the daily-temperature-range significantly became smaller than that in urban areas.Compared with the decreasing trends of annual precipitation and annual rainfall days at rural sites,urbanization increased total precipitation amount.Besides,the urbanization in Beijing slowed down the growth trend of consecutive dry days,and at the same time,it intensified the extreme heavy precipitation events.However,the impact of urbanization on extreme precipitation events is not significant.