基于MODIS数据的重庆市城市热岛效应时空分析

Spatiotemporal distribution of urban heat island effect based on MODIS data in Chongqing,China

随着全球城市化的加速发展,城市热岛现象愈发突出。在重庆市城市化进程中遭遇特大高温灾害的背景下,基于MODIS数据和气象数据,得到重庆市热场强度和强度指数时间序列数据。采用定性和定量分析手段,分析重庆市城市热岛效应的时空变化特征,揭示地表温度与下垫面之间的关系。结果表明:重庆市1951—2016年的年平均气温呈显著上升趋势(P<0.01);重庆市主城区2001—2016年城市热岛面积和强度呈显著增大趋势;城市热岛与环境要素关系密切,归一化植被指数与地表温度呈显著负相关,这说明植被对热场具有调节作用,地表温度与平均气温呈正相关,说明地表对大气具有加热的作用;城市用地、水体、裸地或无植被区域的平均地表温度高于其他下垫面。本研究结果可为重庆市城市规划和生态城市建设提供依据。

With the rapid urbanization,urban heat island phenomena are increasingly obvious. Under the background of high temperature-induced disasters in Chongqing,thermal filed intensity and thermal field intensity index were extracted from MODIS data (2001-2016).Then,we ana- lyzed the spatial and temporal dynamics of heat island effect and its influencing factors.The results showed that the average annual temperature had substantially increased in the past 66years. The area and intensity.of urban heat island had ascended in the downtown of Chongqing from 2001to 2016.Land surface temperature was positively correlated with the average annual temper- ature but negatively correlated with normalized difference vegetation index.Such a result indicates that the air was heated by underlying surface and vegetation could alleviate urban heat island effect.Land surface temperatures of urban land,water,and bare land were higher than that of other land types.Our results can provide effective information for urban planning and eco-city construction in Chongqing.