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，利用生态图表达区域环境文脉，利用卫星感测热像图表达城市热特征。其目的是通过生态和气候图的对比分析，明确城市生态背景对城市热岛形成的影响。首先利用Landsat/TM影像对东京都市圈热岛强度进行了评价。将研究区从东京市中心向西划分为10km区间，并将土地利用划分为8大类，结果表明Landsat/TM热像图的热岛强度与地面气温观测结果吻合较好。这表明卫星热图像可用于评价城市不同土地利用方式和区域间的局部热环境差异。在此基础上，我们利用ASTER/TIR图像对横滨地区进行了地图绘制，并进一步分析了当地的热特征。以栅格热像图和矢量土地利用与建筑图为基础，构建了高密度建成区、绿地区、裸地区和工业用地区4类生态组团图。另一方面，利用ASTER/TIR影像，构建了热点集群、冷点集群、热点特征集群和冷点特征集群4种类型的气候图。对上述地图的生态分析表明，集群内热岛的强度或多或少与它们的面积大小有关。冷地物热岛强度与其几何面积的对数函数关系最强。这些关系也存在于裸地集群、高密度建筑集群等。更重要的是，研究发现冷地物的空间扩展在很大程度上受到区域拓扑环境的影响。丘陵或斜坡上的凉爽特征如果足够大，可能会向下扩散。这解释了热图像在区域尺度上捕捉平流的能力。所有这些发现都是考虑热岛对抗测量的当地气候条件的有价值的信息。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