Observational and analytical studies on influence of urban surface structure on radiation balance components

研究了城市地表结构对地表辐射平衡分量变化的影响。特别是，本研究旨在通过热图像分析，解释城市地面障碍物的额外长波辐射的屏幕效应，即屏幕因子和表面温度。主要研究成果如下：（1）提出了城市及周边地区夜间长波辐射场的基本概念。(2)本文从鱼眼透镜图像中估计了关东地区各城市的屏幕因子（即墙视角因子）的水平分布。结果表明，建筑面积的屏蔽系数约为10 - 75%。（3）对一个结构简单的浆砌石桥墩所用砂岩的岩面温度进行了热图像分析，得到了较好的结果。因此，热示踪法可以用来研究实际的壁面回火状态 关于我们 城市峡谷自然格局。(4)采用热像分析法对一套多层住宅冬季墙体表面温度的增温情况进行了研究，探讨了房间采暖和太阳辐射对墙体表面温度增温的影响。结果表明，太阳辐射对墙体的加热作用大于窗玻璃，室内采暖对窗玻璃的加热作用大于墙体，两者所增加的辐射（4- 26 W/m ~ 2）主要是由于地面障碍物的长波辐射所引起的。(5)各长波辐射平衡分量随屏蔽因子的变化几乎呈线性关系。很明显，额外的长波辐射从城市表面障碍物是充分估计从他们的屏幕效果，如果他们的表面温度分别估计在三种不同的材料的基础上热图像分析。(6)在城市峡谷内，白天的附加长波辐射比夜间增加，但由于太阳辐射的遮荫有效减少，净辐射减少。街道遮阳树可以缓解所有辐射成分。少

Influence due to urban surface structure on the change of radiation balance components in the groundsurface is investigated. In paticular, this study aims at explaining additional longwave radiation from urban surface obstructions by their screen- effects, namelly their screen-factors and surface temperatures based on thermal image analysis. The main results are summarized as follows : (1) The fundamental concept of longwave radiation field at night is proposed in and around urban areas. (2) The horizontal distributions of screen-factor (namelly, wall view-factor) are estimated from a fish-eye lens image in various cities of Kanto region. It is shown that the screen-factor in built-up area is about 10 - 75%. (3)Thermal image analysis is tried on rock-surface temperature of sandstone used for a masonry bridge pier with simple structure, and sufficient results are obtained. Therefore, thermotracer measurement can be applied usefully to investigate the actual states of wall surface temper … More ature pattern in urban canyon. (4) The warming of wall surface temperature in winter is investigated in a maltiple dwelling house by thermal image analysis, and the influences of room heating and solar radiation on its warming are discussed. The results show that solar radiation heats more effectively wall than windowpane and roomheating heats more effectively windowpane than wall, and the increased radiation (4-26W/m2) by the both heating effects are attached great importance to additional longwave radiation from surface obstructions. (5) Every longwave radiation balancecomponent changes almost lineally with the screen-factor. It becomes clear that additional longwave radiation from urban surface obstructions is sufficiently estimated from their screen-effects, if their surface temperatures are estimated separately in three different materials based on thermal image analysis. (6) In the daytimes within urban canyon, additional longwave radiation increases more than at night, but net radiation decreases due to the shade-effective decrease of solar radiation. Street shade trees mitigate all radiation components. Less