城市景观格局与地表温度的定量关系分析

热岛效应是典型的城市气候现象,它的形成及强度与土地利用类型、景观格局等诸多因素有关.本文基于深圳市2010年遥感影像,采用线性光谱混合模型提取土地利用/覆盖等信息,利用最小二乘法和地理加权回归方法分别分析城市景观格局对地表温度的影响.结果表明:深圳市地表温度介于22.28~41.34℃之间,从西北到东南逐渐降低,城市不透水面温度显著高于植被覆盖区域,城市热岛效应明显.地理加权回归模型可以有效处理回归分析中空间非平稳性现象,能更好地刻画景观格局与地表温度之间的定量关系.植被格局指数对地表温度的空间分布解释率较高,其中归一化植被指数(NDVI)、叶面积指数(LAI)对地表温度的解释率最高,分别达88%、90%.不透水面面积、破碎度、邻近度,植被优势种种类、密度、空间分布以及垂直水平生长情况等共同影响深圳市的地表温度.在城市建设实践中,避免不透水面连片集中,降低其邻近度,同时尽可能增加城市的绿地面积,提高NDVI和LAI数值,是缓解城市热岛效应的有效手段.

Quantitative relationship between urban landscape pattern and surface temperature

Urban heat island (UHI) is a typical climate phenomenon,largely attributable to land use and land cover patterns.Land use/land cover conditions in 2010 from remote sensing data were derived by the linear spectral mixture model,to identify correlations between urban landscape patterns and surface temperature all year round by ordinary least squares (OLS) and geographically weighted regression (GWR) models.Temperatures in Shenzhen were found to range from 22.28 to 41.34 ℃,decreasing from northwest to southeast,with significant UHI.GWR model exploring spatial non-stationary of a regression relationship,performed better than OLS model to simulate quantitative relationships between landscape pattern and surface temperature.Vegetation landscape index could explain spatial distribution of surface temperatures.In this regard,normalized difference vegetation index and leaf area index have the highest correlation rates,of 88％ and 90％ respectively.Total area,fragmentation,adjacent impervious surface,species,density,spatial distribution,vertical and horizontal growth conditions of dominant vegetation in combination affect the surface temperature.We demonstrate that by avoiding too much concentrated impervious surface reducing neighboring degrees and improving urban green space NDVI and LAI can effectively alleviate UHI.