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Analysis of heat and moisture trasfer in urbanized area

城市化地区热湿传递分析

基本信息

批准号：
08455226
负责人：
KAWAHARA Yoshihisa
金额：
$ 4.48万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08455226/
关键词：
urban climate heat island water and heat balance land use urban canopy vegetation anthropogenic heat release sea and land breezes 熱収支修正κ-εモデル人工排水蒸気

项目摘要

In the first part, the meteorological data obtained hourly over twenty five years by the Meteorological Agency of Japan and the Tokyo Metropolitan Government were analyzed to detect the trends in temperature and moisture. We found that the daily minimum temperature has been increasing while absolute humidity has stopped decreasing or rather increased recently. Annual balances of water and heat were also studied to confirm the effects of urbanization and annual precipitation on water and heat balances.In the second part, we developed a three-dimensional regional model that takes into account of complex topography, land use, urban canopies and anthropogenic heat and moisture release. The model is made up of four submodels. That is, a heat conduction model in ground, a heat and moisture balance model at ground surface, a surface layr model that is based on the assumption of constant momentum, heat and mass fluxes and an Ekman layr model that solves a set of equations. Here in the Ekman layr model, we adopted a k-e turbulence model modified for stable statification. Through numerical simulation for summer fine days, it is found that the temperature and humidity are affected by land use, sea breeze and that anthropogenic heat release exerts considerable influence on temperature at night while moisture release from cars and human bodies are of minor role.The third part is devoted the analysis of water and heat transfer in ground and at ground surface. A physically-based distribution model was developed to understand the hydrological processes involved. The model performance was tested in the middle reach of Tama river and then applied to Tokyo Metropolis from 1992 to 1994 with the mesh size of 1km and time step of a hour. It is made clear that the changes in land use have led to considerable change in evapotranspiration and the Bowen ratio.

在第一部分中，分析了日本气象厅和东京都政府25年来每小时获得的气象数据，以检测温度和湿度的趋势。我们发现，日最低温度一直在增加，而绝对湿度已经停止下降，而是最近增加。在第二部分中，我们建立了一个考虑复杂地形、土地利用、城市冠层和人为热湿释放的三维区域水热平衡模型。该模型由四个子模型组成。即地下热传导模型、地表热湿平衡模型、基于动量、热量和质量通量恒定假设的表层模型和求解一组方程的Ekman layr模型。在Ekman-layr模型中，我们采用了一个为稳定分层而修正的k-ε湍流模型。通过对夏季晴天的数值模拟，发现夏季晴天的温湿度受土地利用、海风的影响较大，夜间人为热释放对温度的影响较大，而汽车和人体的释湿对温度的影响较小。一个基于物理的分布模型，以了解所涉及的水文过程。1992 ~ 1994年在多摩河中游进行了试验，然后在东京大都会进行了试验，网格尺寸为1 km，时间步长为1小时。结果表明，土地利用方式的改变导致了蒸散量和波文比的显著变化。