北京地区热岛效应及日较差特征

通过对2007～2010年北京地区经质量控制后的123个自动气象站气温数据采用K均值聚类方法分类, 得到城区、郊区、西部和北部山区、西南和东北部山区4个温度分区, 分析了4个分区气温的年变化、日变化和日较差变化特征, 并对北京地区热岛效应的时间变化特征进行了细致分析。结果表明:聚类分析方法可对北京地区温度很好地进行分区, 分区结果与站点的地形和下垫面情况较为吻合;不同分区温度日较差在西部和北部山区最大, 在西南部和东北部山区次之, 郊区再次之, 在城区的日较差最小;在一年中, 各温度分区以2月、5月与10月日较差较大, 其中以5月的日较差为最大;北京地区热岛效应在冬季和夜间较强, 而3～8月热岛较弱, 在夏季的白天比其它季节白天强。

Heat Island Effect and Diurnal Temperature Range in Beijing Area

The K-means clustering method was used to determine quality-controlled hourly surface air temperature data of 123 automatic weather stations in the Beijing area. The sites of these stations were classified into the following four zones, that is urban stations, suburban stations, west and north mountainous area stations, and southwest and northeast mountainous area stations. Monthly and diurnal temperature variations and diurnal temperature range (DTR) of the four zones were analyzed and hourly and monthly urban heat islands were investigated. K-means clustering proved advantageous in classifying temperature zones, which were correlated with the terrain and underlying surfaces of the stations. The DTR of the urban zone was revealed to be smaller than that in suburban and mountainous areas. The west and north mountainous areas exhibited the highest DTR values. All zones exhibited high DTR values in February, May, and October. The urban heat island effect in the Beijing area was stronger in winter and at night. In the daytime, the urban heat island effect appeared to be stronger in summer than that in other seasons. From March to August, the urban heat island effect was the weakest.