Analysis of the Impacts of Regional Environmental Context on the Spatial Structure of Urban Heat Islands with Landscape Ecological Methods

本研究以景观生态学原理为基础，用生态图来表达区域环境背景，用卫星热像气候图来表达城市的热特征。通过对生态图和气候图的对比分析，明确了城市生态环境对城市热岛形成的影响。首先，利用Landsat/TM图像对东京都市区热岛强度进行了评价。将研究区域从东京市中心向西以10公里为间隔进行分区，并将土地利用重新划分为8大类，发现来自Landsat/TM热像仪的热岛强度与地面气温观测结果吻合较好。在此基础上，利用ASTER/TIR影像进行了制图和…分析横滨市更具局部热力特征。基于栅格热像图和矢量化土地利用与建筑物图，建立了高密度建筑群、绿地群、裸地群和工业地群四种类型的生态簇图作为生态图。另一方面，利用ASTER/TIR图像建立了热点、凉点、热点和凉爽4种类型的气候图，对这些图进行了生态分析，结果表明，团内热岛强度与其面积大小有一定关系。凉爽特征的热岛强度与其几何面积具有最强的对数函数关系。这些关系也存在于裸地集群、高密度建筑群等中。更重要的是，研究发现，凉爽特征的空间扩展在很大程度上受到区域拓扑环境的影响。山丘或山坡上的凉爽特征如果足够大，可能会向下蔓延。这解释了热像捕捉区域尺度平流的能力。所有这些发现都是当地气候条件的有价值的信息，用于考虑热岛对策。较少

This study, based on the principles Landscape Ecology, uses ecological maps to express regional environmental contexts and climatic maps from satellite-sensed thermal images to express thermal characteristics of cities. It aims to clarity the impacts of urban ecological contexts on the formulation of urban heat islands through the comparative analyses of ecological and climatic maps.At the first, Landsat/TM images have been used for evaluating the heat island intensity of Tokyo Metropolitan Area. Zoning the study area from the center of Tokyo to west in 10km interval and regrouped land uses into major 8 categories, we found that the heat island intensity from Landsat/TM thermal images gives a good fitness with that from the ground air temperature observation. It implies that the satellite thermal images are applicable to evaluate the differences of local thermal environment between land uses and zones of cities.With the above knowledge, we applied an ASTER/TIR image for mapping and ana … More lyzing local thermal characteristics in Yokohama City. Based on raster thermal images and vector land use and buildings maps, four types of ecological cluster maps including high-densely built-up clusters, green land clusters, bare land clusters and industrial land clusters were created as ecological maps. On the other hand, using the ASTER/TIR image, four types of climatic maps including hot spot clusters, cool spot clusters, hot feature clusters and cool feature clusters were created.The ecological analyses of the above maps show that the intensities of thermal islands within clusters are more or less related to their sizes measured by area. The intensities of heat island of cool features have the strongest logarithmic function with its geometric areas. Theses relationships also exist in bare land clusters, high-densely built-up clusters and so on.More importantly, it is found that the spatial extends of cool features were largely affected by regional topological contexts. The cool feature in hills or slopes may spread downward if it is large enough. This explained the ability of thermal images for capturing the advections in regional scales. All of these findings are valuable information of the local climatic conditions for considering heat island counter measurements. Less