Air-Temperature Response to Neighborhood-Scale Variations in Albedo and Canopy Cover in the Real World: Fine-Resolution Meteorological Modeling and Mobile Temperature Observations in the Los Angeles Climate Archipelago
Air-Temperature Response to Neighborhood-Scale Variations in Albedo and Canopy Cover in the Real World: Fine-Resolution Meteorological Modeling and Mobile Temperature Observations in the Los Angeles Climate Archipelago
复制标题
现实世界中反照率和冠层覆盖的邻近尺度变化的气温响应：洛杉矶气候群岛的高分辨率气象建模和移动温度观测
作者：
H. Taha;R. Levinson;Arash Mohegh;H. Gilbert;G. Ban;Sharon S. Chen
为了识别和表征嵌入在大型城市气候群岛温度场中的局部城市热岛和冷岛信号，采用改进的城市化版WRF气象模式进行了精细分辨率模拟，作为固定天气监测仪选址和移动观测样带设计的基础。目的是描述加州洛杉矶夏季城市温度的变化特征。2016年和2017年夏季，安装在汽车顶部的屏蔽传感器测量的空气温度与模型输出进行了比较，并与地表物理特性（邻里尺度反照率和植被冠层覆盖）相关。该研究模拟并测量了温度对现实世界中已经存在的表面特性变化的响应，即反照率和冠层覆盖度的实际变化，这些变化可以通过当前的建筑和城市设计实践实现。将改进的城市化WRF模式模拟的沿样带温度与洛杉矶市中心附近一个地区和内陆盆地（圣费尔南多谷）15个移动通道的沿样带观测温度进行了比较。观察到的样条温度也与为输入模型而开发的表面物理特性特征相关。这两个比较结果都是有利的，这表明：(1)该模型可以可靠地用于固定气象站的选址和设计移动样带路线来表征城市热量；(2)除了少数具有相反共变影响的情况外，观测温度与反照率之间以及观测温度与冠层覆盖度之间的相关性均为负，反照率每增加0.1°C至−9.0°C，冠层覆盖度每增加0.1°C至−2.2°C。分析区域的观测数据表明，风速阈值为3米/秒。在这个阈值以下，气温的变化可以用每个观测点500米半径内的土地利用和地表性质来解释。在该阈值以上，空气温度受1 km范围内逆风天气的影响。与政策建议相关的是，该研究证明了增加城市反照率和植被冠层覆盖对现实世界的显著冷却效应。基于观测温度（来自移动样带）与研究区域表面物理性质之间的相关性，分析表明，通过增加反照率，可以在白天实现高达2.8°C的邻域尺度（500米）降温。通过增加树冠覆盖，一个社区白天可以降温2.3°C，晚上可以降温3.3°C。分析还表明，使用高分辨率气象模型设计移动样带路线或定点天气监测仪，可以量化城市热量以及反照率和冠层覆盖对策的有效性。结果表明，该模型能够较准确地预测局部城市冷热岛的地理位置和大小。因此，模型结果也可用于设计城市热缓解措施。
To identify and characterize localized urban heat- and cool-island signals embedded within the temperature field of a large urban-climate archipelago, fine-resolution simulations with a modified urbanized version of the WRF meteorological model were carried out as basis for siting fixed weather monitors and designing mobile-observation transects. The goal was to characterize variations in urban heat during summer in Los Angeles, California. Air temperatures measured with a shielded sensor mounted atop an automobile in the summers of 2016 and 2017 were compared to model output and also correlated to surface physical properties focusing on neighborhood-scale albedo and vegetation canopy cover. The study modeled and measured the temperature response to variations in surface properties that already exist in the real world, i.e., realistic variations in albedo and canopy cover that are attainable through current building and urban design practices. The simulated along-transect temperature from a modified urbanized WRF model was compared to the along-transect observed temperature from 15 mobile traverses in one area near downtown Los Angeles and another in an inland basin (San Fernando Valley). The observed transect temperature was also correlated to surface physical properties characterizations that were developed for input to the model. Both comparisons were favorable, suggesting that (1) the model can reliably be used in siting fixed weather stations and designing mobile-transect routes to characterize urban heat and (2) that except for a few cases with opposite co-varying influences, the correlations between observed temperature and albedo and between observed temperature and canopy cover were each negative, ranging from −1.0 to −9.0 °C per 0.1 increase in albedo and from −0.1 to −2.2 °C per 0.1 increase in canopy cover. Observational data from the analysis domains pointed to a wind speed threshold of 3 m/s. Below this threshold the variations in air temperature could be explained by land use and surface properties within a 500-m radius of each observation point. Above the threshold, air temperature was influenced by the properties of the surface within a 1-km upwind fetch. Of relevance to policy recommendations, the study demonstrates the significant real-world cooling effects of increasing urban albedo and vegetation canopy cover. Based on correlations between the observed temperature (from mobile transects) and surface physical properties in the study domains, the analysis shows that neighborhood-scale (500-m) cooling of up to 2.8 °C during the daytime can be achieved by increasing albedo. A neighborhood can also be cooled by up to 2.3 °C during the day and up to 3.3 °C at night by increasing canopy cover. The analysis also demonstrates the suitability of using fine-resolution meteorological models to design mobile-transect routes or site-fixed weather monitors in order to quantify urban heat and the efficacy of albedo and canopy cover countermeasures. The results also show that the model is capable of accurately predicting the geographical locations and the magnitudes of localized urban heat and cool islands. Thus the model results can also be used to devise urban-heat mitigation measures.
影响因子：
6.7
作者：
M. Taleghani;D. Sailor;G. Ban-Weiss
通讯作者：
M. Taleghani;D. Sailor;G. Ban-Weiss