Studies on the optimum arrays of roadside trees in an urban canyon considering thermal effect in summer

本研究探讨了建筑物和路边树木的布局对遮阳的街道上，特别是在人行道上的影响，使用平均辐射温度的预测热环境的评估。其基本参数是建筑物高度、街道宽度、一排树木的数量和树冠的大小。采用夏季天气、网格式街道和球形树冠的假设，利用红外摄像机测量的树冠表面温度的多元回归方程，模拟了街道的热环境。计算了13种建筑物和行道树布局的街道平均辐射温度，发现两侧建筑物的高度越低，行道树对街道的散热效果越好。很明显，树木的数量和树冠的大小越大，街道上的平均辐射温度越低，特别是在城市峡谷的人行道上。

This study examines the effects of the layouts of buildings and road side trees on solar shading on the streets, particularly on the footpath, using mean radiant temperature for the evaluation of predicted thermal environment. The basic parameters are buildings height, width of the streets, the number of trees in a row and the size of trees crown. Thermal environments on the streets are simulated assuming summer weather, grid type streets and spherical foliage crowns and using the multiple regression equation of surface temperature of foliage crown measured by infra-red camera. Calculations of mean radiant temperature are carried out on the streets of 13 layouts of buildings and roadside trees.Roadside trees mitigate more extensive heat on the streets if the height of buildings on its both sides is lower. It is clear that the larger the number of trees and the size of foliage crowns in a row, the lower is mean radiant temperature on the streets, especially on the footpath in an urban canyon.