上海市城市化进程中热环境响应的空间评价

利用Landsat TM/ETM+ 遥感数据解译与反演得到上海市1997~2009年的土地利用/覆盖类型图及热岛强度分布图,并分析其演变趋势,引入温度-植被指数(TVX)并采用TVX空间法定量研究了以建设用地扩张、生态用地减少为特点的城市化过程引起的热环境效应.研究表明,1997~2009年,上海市人口呈现从中心城至郊区的流动趋势;热岛强度分布与城市化建设密切相关,呈现“葫芦串-葡萄串-摊大饼型”的蔓延模式;以牺牲生态用地为代价的建设用地扩张造成研究区域地表温度的上升及植被覆盖度的下降,其中林地减少所引起的热环境效应最大.研究可为城市规划决策过程中不同城市化空间的拓展情景提供其可能的环境响应结果,从而完善气候变化适应性对策,推进城市生态系统的可持续发展.

An assessment of spatial thermal environmental response to rapid urbanization of Shanghai

The Landsat TM/ETM+ images, from 1997to 2009, were used to analyze temporal changes of land use, land cover changes and urban heat island intensity. The relationship between temporal climatic variability and land use types was examined by an innovative construction of temperature vegetation index (TVX) space. Results show that Shanghai has undergone significant changes in land use and land cover over the study period. The land conversion, from forest land, farmland and water body to urban area, has led to the drastic increase of land surface temperature and the decline of fractional vegetation cover. The loss of forest land had the most serious climatic effect. Furthermore, the high-temperature region has expanded by different modes, from “Bottle Gourd Mode” to “Grape Bunch Mode” and to “Pancake mode” due to rapid urbanization and the population migration from city proper to rural areas. Our study could help urban planners and decision-makers to evaluate the environmental consequences of different land development scenarios, and identify portfolios of sustainable urban planning options for adapting to global environmental change.