北京城市空间形态对热岛分布影响研究

Influence of Beijing spatial morphology on the distribution of urban heat island

在城市尺度上探究城市空间形态布局对城市热岛(UHI)影响研究,对于城市规划中通风环境改善、生态宜居城市建设具有重要意义。以北京为例,利用2009—2018年高密度自动气象站逐小时气温资料和2018年NPP/VIIRS夜光卫星资料,分析了UHI时空分布特征;利用2017年1∶2000基础地理信息和Landsat8卫星资料,开展了北京主城区建筑高度(BH)、建筑密度(BD)、建筑高度标准差(BSD)、容积率(FAR)、迎风截面积指数(FAI)、粗糙度长度(RL)、天空开阔度(SVF)、城市分数维(FD)等8个空间形态参数和植被覆盖度(VC)、不透水盖度(IC)、反照率(AB)等3个陆表参数的提取,并在城市尺度上开展了这些参数与UHI之间空间相关性及对UHI变化影响研究。结果显示:2009—2018年北京主城区年均、四季以及夜晚02时UHI均存在一个较为固定的形态,年均、春、夏、秋、冬、白天14时和夜晚02时UHI分别为1.81℃、1.50℃、1.43℃、2.16℃、2.17℃、0.48℃和2.77℃;8个空间形态参数在一年中大部分时段与UHI存在明显空间相关性,这种相关性在冬季强于其他季节,在夜晚02时强于白天14时,排名前三的分别为SVF、FAR和BD。空间形态参数已超越陆表参数成为UHI变化的重要驱动因子,11种参数对UHI变化的单独贡献为13.7%~63.7%,其中夏季、冬季和全年时段贡献最大的空间形态参数分别是BD(43.7%)、SVF(63.7%)和SVF(45.4%),贡献最大的陆表参数分别是VC(42.6%)、AB(57.1%)和VC(45.3%);夏季、冬季和全年时段多个参数对UHI变化的综合贡献分别为51.4%、69.1%和55.3%,主导要素分别为BD、SVF和BD。

Exploring the influence of urban spatial morphology layout on the urban heat island(UHI)at the urban scale is of great significance for the improvement of ventilation environment and the ecological and livable urban planning.Taking Beijing,China as an example,this study analyzed the UHI spatial characteristics using the hourly temperature data of high-density automatic weather stations in 2009-2018 and the 2018 NPP/VIRRS night-light satellite data.Using 1:2000 basic geographic information data and Landsat8 satellite remote sensing data in 2017,based on remote sensing and GIS technology and morphological models,we extracted eight morphological parameters in the main urban area of Beijing,namely,building height(BH),building density(BD),building standard deviation(BSD),floor area ratio(FAR),frontal area index(FAI),roughness length(RL),sky view factor(SVF),fractal dimension(FD)and three land surface parameters consisting of vegetation coverage(VC),impervious cover(IC),albedo(AB).The relationship between these morphological parameters and UHI was further examined at the urban scale using the spatial statistical method.Results show that the downtown area of central Beijing has presented a relatively fixed distribution pattern of UHI at annual scale,four seasons,and 02:00 at nighttime in the past 10 years.The UHI of the annual,spring,summer,autumn,winter,14:00,and 02:00 are 1.81℃,1.50℃,1.43℃,2.16℃,2.17℃,0.48℃,and 2.77℃,respectively.The eight spatial morphological parameters have obvious spatial correlations with UHIs for most of the year,and the correlations are stronger in winter than in other seasons,and stronger at 02:00 am than at 14:00 pm.The top three parameters are SVF,FAR,and BD.There are spatiotemporal changes in the impact of different spatial morphological parameters and land surface parameters on UHI.Spatial morphological parameters have become important drivers of UHI change and the individual contributions of the eleven parameters to UHI changes are 13.7%to 62.2%.The spatial morphological parameters that contribute the most in summer,winter,and the whole year are BD(43.7%),SVF(62.2%),and SVF(43.0%),respectively;and the corresponding largest land surface parameters are VC(42.6%),AB(57.1%),and VC(45.4%),respectively.The comprehensive contribution of multiple parameters to UHI changes in summer,winter,and the whole year are 51.4%,69.1%,and 55.3%,respectively;and the dominant influencing factors are BD,SVF,and BD.