城市化进程对南京市区域气温变化的影响

20 世纪90 年代以来中国进入城市化快速发展阶段,城市规模迅速扩张,这在一定程度上对大气热环境产生了影响,如产生了城市热岛效应.文章基于南京气象站点观测数据、南京市统计年鉴以及landsat TM 影像数据,选取人口密度、废气排放量、运营车辆、用电量、绿地覆盖面积、建成区面积6 项指标构建城市化因子群,运用灰色关联度分析法对影响南京气温变化的因子群进行贡献度分析.首先,基于以往研究及南京市统计年鉴选取人口密度、废气排放量、运营车辆、用电量、绿地覆盖面积、建成区面积6 项指标构建城市化因子群;其次,基于landsat TM 影像数据利用监督分类方法提取建成区面积;最后,基于灰色关联度分析方法,定量计算出人口密度、废气排放量、运营车辆、用电量、绿地覆盖面积、建成区面积6 项城市化因子分别对年均温、年最高温、年最低温、季均温、月均温以及不同时期温度均值的影响.研究发现,（1）1983-2011 年期间,南京市气温呈明显递增趋势,20 世纪90 年代后期增温更为明显,1999-2007 年年均温增长了1.50 ℃.（2）发现对于同-参考数列（年均温、月均温等）而言,其影响因子关联度整体排序是一致的：人口密度〉建成区面积〉废气排放量〉运营车辆〉用电量〉绿地覆盖面积.（3）同一城市化因子对年均温变化、年最高温变化、年最低温变化的影响是不相同的.例如,人口密度对1983-2011 年年均温变化影响最大,关联度达到了0.95;用电量、废气排放量和运营车辆对1983-2011 年年最低温变化影响最大,其关联度分别为0.68、0.74、0.73.（4）同一城市化因子对不同月份气温变化的影响是不相同的,如人口密度与2 月月均温之间的关联度最小,关联度为0.78;与3 月月均温之间的关联度最大,关联度为0.93.（5）不同城市化因子随着时间的推移,对区域气温变化的

Influence of Urbanization on the Temperature Changes in Nanjing

Due to the long period of rapid urban development since 1990’s, the atmospheric thermal environmental impact has beeninfluenced to some extent in many Chinese cities, resulting in significant urban heat island effect. In this paper, potential indicatorsare proposed to identify major urbanization factors in Nanjing which may have significant influence on the regional temperaturechanges based on analyzing the Nanjing meteorological observation data, statistical yearbook of Nanjing city and the Landsat TMimage data. The grey correlation degree analysis method is adopted to analyze the factor contributions on the influence oftemperature variation. Firstly, based on the previous research and the statistical yearbook of Nanjing, six potential indicatorsincluding the population density, exhaust emissions, vehicles in operation, power consumption, green coverage area and built-up areaare selected for assessment. Secondly, built-up areas were extracted based on multi-temporal Landsat TM images using a supervisedclassification method. Finally, the correlation degrees between the population density, exhaust emissions, vehicles in operation,power consumption, green coverage area and, built-up area, and the annual mean temperature, the maximum temperature, theminimum temperature, the seasonal mean temperature and the monthly mean temperature are calculated by the grey relational degreeanalysis method, respectively. The results show that： （1） During the period of 1983─2011, the temperature of Nanjing are shown asan increasing trend, especially since later period of 1990’s. The absolute temperature increase is 1.5℃ in 1999─2007. （2） It is foundthat for the same reference sequence （annual mean temperature, monthly mean temperature, etc.）, the overall ranking order of theinfluence factors’ relevance remains no change, i.e., population density 〉 built-up area 〉 exhaust emissions 〉 vehicle in operation 〉power consumption 〉 green cover area. （3） However, the influence of the same factor to the