长沙都市区热力景观空间格局分析

Analysis on Spatial Gradients Pattern of Thermal Environment Landscape in Changsha Metropolitan Area

热环境是城市生态系统的重要组成部分,将分形几何学的基本理论引入地表热力景观格局研究,可以量化评价城市热环境状况。以长沙都市区为例,利用TM热波段反演得到地表温度,并将其分为强热岛、弱热岛、常温区、弱冷岛和强冷岛5种热力景观类型,分别采用standard法和moving window法分析了都市区热力景观空间格局,然后用边界维数D和稳定指数SK定量化地描述了热力景观格局的复杂度与稳定性。结果显示:常温区是热力景观基质,而热岛景观已是春季城市热场重要特征;景观梯度变化在南北和东西两条样带上均呈现由市区向乡村骤变的特征,并伴有不同幅度的波动;热力景观边界维数D复杂度排序为:常温区>弱热岛>弱冷岛>强热岛>强冷岛,稳定性指数SK排序与之相反。

Thermal environment is a very important composition of urban ecosystem. This paper integrates some theories of fraCtal and quantitative methods into the study on thermal environment issue.s, and the spatial gradients pattern of thermal environment landscape in Changsha metropolitan area. As retrieving land surface temperature （LST）using single-channel algorithms from LANDSAT TM data in 2009 ,and dividing LST into five thermal environment landscape types,that is, strong heat island,weak heat island, normal temperature areas,weak cool island and strong cool island. With the support of ArcG-IS, aims to analyze complete landscape patterns and its spatial differences within the whole basin through standard methods and moving window analysis of Fragstats, the spatial gradients patterns of thermal environment landscape in Changsha metropolitan area of class level and landscape level are ealculated. It＇s showed the results as followings： 1）normal temperature areas compose a major part in Changsha metropolitan area on 2009, and the landscape of heat island （including strong heat island and weak heat island）, accounting for 28. 28 % of the total landscape, is an important characteristic of thermal environment; 2）two transects show similar features：they fluctuate in different amplitudes along these transects as landscape types changes, and both not existing evident transitional zone; 3）each thermal environment landscape factor can be ranked according to the fractal dimension D in the terms： normal temperature areas 〉 weak heat island 〉 weak cool island 〉 strong heat island 〉 strong cool island. And each thermal environment landscape factor can be ranked of the mosaic structure of the level of stability （SK） ：strong cool island 〉 strong heat island 〉 weak cool island 〉 weak heat island 〉 normal temperature areas. Fractal theory has significance on research of urban heat island.