近20年来重庆市主城区地表热岛的时空变化

Spatial-Temporal Changes of Surface Heat Island in the Central Area of Chongqing over the Past 20 Years

为了揭示快速城市化地区热岛的时空变化特点,以重庆市主城区为例,利用1988─2009年共5个时期的TMETM+影像反演地表温度,分析了地表热岛和相对热岛强度的空间格局及其变化趋势.结果表明:近20年来地表热岛的空间格局经历了集聚→较集聚→集聚的演变过程,热岛逐渐由重庆市老城区向外围城市组团转移;最大的相对热岛强度总体呈先增大后减小的变化趋势;老城区的相对热岛强度明显减弱,外围新兴城市组团相对热岛强度显著增加,沿长江和嘉陵江的开发建设导致滨江带相对热岛强度明显增强;相对热岛强度增强幅度与减弱幅度基本相当,大部分地区的相对热岛强度变化较平缓.相对热岛强度及其时空变化与重庆市扩张十分吻合,具有显著的城市组团式特点.

To reveal the spatial-temporal changes of the urban heat island in rapidly urbanizing areas,the spatial-temporal changes of surface heat island and relative intensity of surface heat island of Chongqing were analyzed by the GIS spatial analysis functions.The land surface temperatures（LST） in the central area of Chongqing in 1988,1993,2001,2007 and 2009 were retrieved using Landsat TM/ETM＋ thermal data.The results showed that： 1） over the past 20 years,the spatial pattern of surface urban heat island experienced an evolution from clustered pattern to less clustered pattern,and then again to clustered pattern;2） the maximum relative heat island intensity increased initially and then decreased;3） the relative heat island intensity decreased significantly in the old city zone,but increased significantly in the new city groups outside;the relative heat island intensities in the riverside zones near the Yangtze and Jialing Rivers increased significantly as a result of strong construction activities;4） the reduced magnitude of the relative heat island intensity in the old city zone was almost equal to the increased magnitude of relative heat island intensity in the new groups outside,and the relative heat island intensity showed a gentle trend in most parts of the study area.The relative heat island intensity changed consistently with the rapid expansion of the city spatially and temporally,and clearly followed the clustered urban structure.