测绘学报

• 学术论文 •    

城市扩展强度及其地表热特性遥感定量分析

曾永年,张璎璎,郑文武,黄炜,张鸿辉   

  1. 1. 中南大学信息测绘与国土信息工程系
    2. 中南大学
  • 收稿日期:2008-12-16 修回日期:2009-03-02 出版日期:2010-02-22 发布日期:2010-02-22
  • 通讯作者: 曾永年

A quantitative analysis of urban growth and associated thermal characteristics using remote sensing data

  • Received:2008-12-16 Revised:2009-03-02 Online:2010-02-22 Published:2010-02-22

摘要: 城市化将自然景观转变为不同土地利用的城市景观,改变了地表的物理特性。因此,有关城市扩张及其对环境的影响的准确信息具有广泛的应用价值。利用遥感技术监测土地利用变化成为城市环境研究的重要内容,然而利用遥感技术定量提取城市扩展及其强度的定量信息仍存在许多挑战。本文提出了定量确定城市扩展范围及其发展强度的新方法——地图密度指数。并以中部城市——长沙为例,利用Landsat TM/ETM+数据定量评价了城市扩张及其热环境特征的变化。首先,集成遥感光谱指数提取地表非渗透表面,然后利用移动窗口算法获得地图密度指数,再根据设定的阈值获得密度指数等级图,依此密度指数等级图识别城市扩展范围及其发展强度。再结合地表温度反演的数据,分析了城市格局及其变化与地表热特性变化的定量关系。结果表明,自1990年代以来,长沙市城市区域及其发展密度显著增加,城市发展的密度差异与地表温度相一致。 地图密度指数能较好刻画城市扩展范围及其发展强度,并与地表温度空间分布存在较好的对应关系。

Abstract: Urbanization transforms the natural landscape to anthropogenic urban land use and changes surface physical characteristics. Accurate information on the extent of urban growth and its impacts on environment are of great interest for diverse purposes. As a result, increased research interest is being directed to the mapping and monitoring of urban land use using remote sensing techniques. However, there are many challenges in deriving urban extent and development densities quantitatively. This study utilized remote sensing data of Landsat TM/ETM+ to assess urban sprawl and its thermal characteristics in Changsha of central China. A new approach was proposed for quantitatively determining urban land use extents and development densities. Firstly, impervious surface areas were mapped by integrating spectral index derived from remotely sensed data. Then, the urban land extents and development densities were identified by using moving window calculation and selecting certain threshold values. The urban surface thermal patterns were investigated using Landsat thermal band. Analysis results suggest that urban extent and development density and surface thermal characteristics and patterns can be identified through qualitatively based remotely sensed index and land surface temperature. Results show the built-up area and urban development densities have increased significantly in Changsha city since 1990s. The differences of urban development densities correspond to thermal effects where higher percent imperviousness is usually associated with higher surface temperature. Remotely sensed index and land surface temperature are demonstrated to be very useful sources in quantifying urban land use extent, development intensity, and urban thermal patterns.