城市空间三维变化对城市冷桥效应影响机理分析与模拟模型研究

Continued urbanization has caused urban heat accumulating excessively in micro-environment. This environment problem has limited livable City development seriously. The urban cool bridge is an important issue for alleviating this problem, but less mechanism study has been conducted about the urban cool bridge effect. The specific objective of this study is to construct a simulation model to characterize effects of three-dimensional urban space changes on the dynamics of urban cool bridge. As a typical area which has experienced significant dynamic process of cold bridge effect, Beijing Olympic Village area is taken as the test area. Multi-source high spatial resolution remote sensing data sets, including Quickbird satellite images, aerial remote sensing stero pair, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) thermal infrared data as well as Chinese national thermal infrared data with 10 meters spatial resolution over the test area, are employed together for the temporal-spatial information extraction. Geographical finite element method is introduced to analyze the response mechanism of urban cool bridge to three dimensional urban dynamics. In order to introduce this method properly, four key scientific or technical issues will be studied carefully. Firstly, appropriate spatial scale will be analyzed before constructing the space discrete grid model. Second, sensitive parameters of urban cold bridge effect to three-dimensional urban space dynamic will be researched. On the basis of the sensitive parameters, cold bridge effect of local nonlinear response function will be established by spatial regression analysis and finite element analysis. This response function is then used as the finite element boundary conditions in the model. Three couples of three dimensional urban space and urban cool bridge reality data extract from remote sensing data in three typical periods, which represents three different conditions of uContinued urbanization has caused urban heat accumulating excessively in micro-environment. This environment problem has limited livable City development seriously. The urban cool bridge is an important issue for alleviating this problem, but less mechanism sturban cold bridge, are run by the model in order to integrating the results thus to optimize the simulation model and its parameters. Finally, the development of model characterizing effects of three-dimensional urban space changes on the dynamics of urban cool bridge is completed. A new high spatial satellite data in 2013 and synchronization field measurements data will be used to validate the model and evaluate the model accuracy. The study results will create new knowledge about how the urban cool bridge response to the urban three dimensional dynamics. This new mechanism analysis and simulation model has good potential applications values for optimizing the three dimensional urban space and reasonable construction of the urban cold bridge system.

城市热量过度积聚作为城市化产生的微观环境异常问题，严重阻碍着城市的宜居和发展，城市冷桥效应对缓解该问题有积极作用，但目前缺乏对其机理性定量研究。本研究以构建城市空间三维变化对城市冷桥效应影响模拟模型为研究重点，选择经历城市冷桥效应显著变化过程的北京市奥运村地区为典型试验区，利用多源多时序高分辨率遥感数据集，定量表达和分析城市三维空间变化及对应城市冷桥效应的特征因子；引入地理有限元方法，选取合适尺度构建问题空间离散网格模型，挖掘影响城市冷桥效应的城市空间三维特征敏感参量，建立局域非线性城市冷桥效应响应函数作为有限元边界条件，综合多期对有限单元问题空间中城市冷桥效应求解的结果，优化模拟模型及其参量，实现城市空间三维变化下城市冷桥效应模拟模型构建。研究结果将为城市三维空间变化影响城市冷桥效应的机理提供新的认知，在优化城市空间分配、合理构建城市冷桥系统方面具有很好的应用潜力。

城市热量过度积聚作为城市化产生的微观环境异常问题，严重阻碍着城市的宜居和发展。从城市三维形态的角度研究其对城市热环境的影响，有助于协调发展与环境保护之间的矛盾问题。本研究以构建城市空间三维变化对城市冷桥效应影响模拟模型为研究重点，选择经历城市冷桥效应显著变化过程的北京市奥运村地区为典型试验区，利用多源多时序高分辨率遥感数据集，定量分析了城市三维空间变化及对应城市热环境的影响，构建了二者之间的关系模型。在城市三维形态因子当中，对城市冷桥效应影响显著的仍然是绿地和水体的面积和植被指数的高低。城市垂直维形态对城市冷桥效应的贡献率次于地表覆盖的物理特性。就垂直维形态特征来讲，建筑物高度越高，其越有可能构建峡谷廊道，促进风的流动进而达到降温的目的。此外，高建筑物的阴影也是降温的因素之一。但进一步结合建筑物体积密度与城市冷桥效应的影响关系来看，并非高丛林里的高楼即可以解决城市热量过度聚集的问题。建筑体积分布密度是一个重要的限制因素。建筑体积分布密度在30m栅格尺度下的转折点为20.6。低于该转折点时，即建筑体积密度越低，温度越高，如水泥地面的广场、低矮的工业用地区及厂房车库等的增温作用要大于6-10层左右的居民区、办公区。当建筑体积密度超过该临界值时，如高楼林立且密集的写字楼、居民楼等，其增温作用是随着建筑体积密度增加而逐渐增加。研究结果将为城市三维空间变化影响城市冷桥效应的机理提供新的认知，在优化城市空间分配、合理构建城市冷桥系统方面具有较好的应用潜力。