The observational climate data during 1961 - 2008 are used to investigate the features of the seasonal and interannual variations of temperature, precipitation, relative humidity, and wind speed over the urban and rural areas in Beijing and the effects of urbanization on the regional climate in Beijing are discussed. The results show that,over the past half century, the average temperature has an increasing trend, in particular in the winter season, and there is a weaker signal in the summer season. By analyzing the decadal variations of the temperature, it is found that this increasing trend has become stronger in recent decades, enhancing the effects of urban heat island, especially after the 1990s. Both the maximum and minimum temperatures show increasing trend in recent 48 years and the urbanization has the most important effects on the minimum temperature followed by the average temperature, and has the weakest effects on the maximum temperature For precipitation, there is a decreasing trend, in particular for the summer season. Over the urban areas, both wind speed and relative humidity show decreasing trend which is closely related to the urbanization, especially to the changes of the surface types.%利用1961～2008年北京12个台站的气候观测资料,研究分析了北京城区和郊区气温、降水、相对湿度、风速的年际和四季变化趋势及特点,并探讨了城市化发展对北京区域气候的影响.结果表明:近半个世纪以来,平均气温上升明显,其中尤以冬季最为突出,而夏季最弱.通过气温变化的年代比较发现气温增加有加快的趋势,尤其是城市地区,导致热岛效应不断加强,特别是1990年代以后增幅更加明显.最高和最低气温在近48年来也都呈上升趋势,且城市化发展对最低气温的变化影响最大,其次是平均气温,对最高气温影响最弱.而降水有减弱的趋势,尤其是夏季的降水减弱最为明显.城区的风速和湿度都呈减小的趋势,这与城市化的加剧,尤其是下垫面的变化有密切的关系.
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