基于3D建筑物数据的天空开阔度估算及其城市热岛应用研究——以Adelaide为例

城市热岛效应(Urban Heat Island,UHI)越来越受关注,城市冠层之间的辐射传输和交换受到周围建筑物阻挡,是城市热岛现象产生的重要原因之一。天空开阔度是描述天空被建筑物阻挡程度的形态学参数,经常被用于城市热岛现象研究中。以澳大利亚Adelaide中心城区为研究区,基于高分辨率的3D建筑物数据计算天空开阔度(SVFs),并与鱼眼技术方法计算的SVFfish-eye值进行对比,在此基础上分析了不同季节、不同时刻的SVFs与城市热岛强度之间的相关关系。结果表明:SVFs与SVFfish-eye非常吻合,二者之间的相关系数为0.97;SVF和UHII(城市热岛效应强度)在无雨天气下的夜间都呈显著线性负相关,在夏季、秋季和冬季的中午附近,两者呈明显的线性正相关,而在春季的中午附近,两者的线性正相关不明显;对于晴天、阴天和雨天3种天气来说,SVF和UHII在夜晚的负相关性差别不大;在白天,晴天的正相关性大于阴天和雨天。

Sky View Factor Estimation based on 3D Urban Building Data and Its Application in Urban Heat island——Illustrated by the Case of Adelaide

Urban heat island (UHI) phenomenon has attracteds more and more attention.Radiative transfer and exchange between urban canopy is blocked by the surrounding buildings,which is one of the important reasons for urban heat island phenomenon.Sky view factor is a morphological parameter that describes the degree to which the sky is obscured by building block,and has been commonly used to analyse UHI.In this study,SVFs was estimated by 3D building data with a high spatial resolution for Australia Adelaide central city,and compared with SVFfish-eye calculated from fish\|eye photos.On the basis,the paper discussed the relationship between SVFs and urban heat island intensity(UHII) in different times of various seasons.The results show that SVFs is very consistent with SVF fish-eye,and the correlation coefficient is 0.97;and there exist a high negative linear relationship between SVFs and UHII at night time for all seasons under clear weather conditions.The correlations are significant positive in the noon of the summer,autumn and winter;while the positive linear correlation is not obvious in Spring.Under clear,cloudy and rainy weather conditions,there are little difference between SVF and UHII at night time,however,the positive correlation under clear sky is greater than that under cloudy and rainy weather conditions in daytime.