成渝城市群城镇化的热岛效应

Heat island effect during the process of urbanization in Chengdu-Chongqing urban agglomeration

热岛效应是城镇化对生态环境的重要影响之一,科学评价城镇化过程中热岛效应的时空变化对于新型城镇建设具有重要意义。成渝城市群位于中国西部,是由成都-重庆2个特大城市,以及14个大、中、小城市组成的城市群,近年来城镇化的快速发展,使得热岛效应日益突出。本研究利用MODIS/Terra卫星2000—2010年的逐月地表温度数据,计算成渝城市群内16个城市城区和城市郊区的平均温度之差,进而分析城市群的热岛效应。结果表明:(1)成渝城市群存在较为明显的四季和昼夜的热岛强度差异;(2)特大城市重庆市和成都市的热岛效应明显强于其他大、中、小型城市,城市群内建成区规模与城市日间热岛强度呈显著的相关性;(3)2000—2010年所有城市的热岛效应呈减弱趋势,10年间热岛强度下降0.3℃。老城区热岛强度10年间平均上升0.21℃,其中日间热岛强度变化较小,夜间热岛强度呈显著上升趋势。

Heat island effect is one of the most striking impacts of urbanization on eco-environ- ment. It is important for the construction of new cities to evaluate the temporal and spatial change of heat island effect during the process of urbanization. Chengdu-Chongqing urban agglomeration is located in the western part of China, consisting of 2 megalopolis and 14 large-, medium-, and small-sized cities. The heat island effect is increasingly outstanding in recent years due to the de- velopment of urbanization in these areas. In this study, based on the MODIS/Terra monthly land surface temperature （LST） data from 2000 to 2010, we analyzed the heat island effect of Cheng- du-Chongqing urban agglomeration by calculating the difference of average temperature between urban and rural areas of the 16 cities. The results showed that ： （ 1 ） The seasonal and diurnal heat island effect in Chengdu-Chongqing urban agglomeration was relatively obvious. （2） The heat island intensity in mega-cities Chengdu and Chongqing was greater than in the other 14 cit- ies, and a significant correlation was observed between the built-up area and the daytime heat is- land intensity. （3） The overall heat island intensity decreased by 0.3 ℃ during 2000 and 2010. In the meantime, the heat island intensity in old towns increased by 0.21 ℃, and the change was slight in the daytime and significant in the nighttime.