中文摘要：

利用北京地区城郊16个气象观测站1979～2008年逐日平均、最高和最低温度的均一化资料,分析了近30年北京地区城、郊区极端温度事件发生频次（强度）的变化趋势,并对比了城郊差异以及城市热岛强度对城郊差异的影响。研究结果显示：从发生频次来看,近30年城区极端低温事件的减小幅度[-5.94d（10a）-1]高于郊区的减小幅度[-5.28d（10a）-1],而极端高温事件的增加幅度在城区[4.33d（10a）-1]和郊区[4.42d（10a）-1]之间差别不大,定量化的诊断结果进一步证明了城区和郊区在极端温度事件发生频次上的差别很小。从发生强度来看,近30年城区极端温度事件的年平均发生强度明显高于郊区,但在变化趋势上,城区极端低温事件的减弱幅度略高于极端高温事件的增强幅度,相差0.042℃（10a）-1,而在郊区极端低温事件的减弱幅度却略低于极端高温事件的增强幅度,相差0.052℃（10a）-1。城郊差异的定量化分析结果表明,极端温度事件在城区强度一般大于郊区强度,城区与郊区强度差值均为正值（除1982年和1985年极端高温事件强度差值为负）。热岛强度与极端温度事件城郊差异的相关性统计发现,极端温度事件发生频次和发生强度在城郊之间的差别与热岛强度均没有明显的相关特征,该结果说明城市热岛效应对北京超大城市市区和郊区影响基本一致,其差异性是有限的。

英文摘要：

The frequency and intensity of temperature extremes in Beijing was studied by using the standardized weather station data from 1979 to 2008. The differences between rural and urban areas and their relationship to the urban heat island intensity are discussed. The analysis results show that the decrease in the minimum temperature events over the urban area [-5.94 d （10 a）-1 ] was slightly higher than that over rural areas [-5.28 d （10 a）-1 ] over the 30-a period, while the difference of maximum temperature changes between the urban [4.33 d （10 a）-1 ] and rural [4.42 d （10 a）-1 ] areas were much smaller. The authors also found that the frequencies of extreme events between the urban and rural areas were very small. The investigation of the intensity revealed similar trends. Although the temperature extremes over the urban area were clearly stronger than over the rural areas, in the urban area the decreasing trend of minimum temperature extremes was slightly greater [0.042 °C （10 a）-1 ] than the increasing trend of the maximum temperature extremes, while in the rural area the deceasing trend of the minimum temperatures was slightly less [0.052 °C （10 a）-1 ] than the increasing trend of the maximum temperatures. The study on the differences between the urban and rural areas suggested that the intensity of the temperature extremes was stronger over the urban area than that over the rural area. The difference in temperature extremes ship between the urban and rural areas was generally a positive value （except for the negative difference in maximum high temperature in 1982 and 1885）. On the other hand, statistical analysis showed no correlationship between the intensity of the urban heat island and the rural–urban difference of extreme temperature events, indicating that the impact of the urban heat island on the urban and rural areas is mainly coincident for a super-city like Beijing.