Modelling spatiotemporal variations of the canopy layer urban heat island in Beijing at the neighbourhood-scale
Modelling spatiotemporal variations of the canopy layer urban heat island in Beijing at the neighbourhood-scale
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DOI：
10.5194/acp-2020-931
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发表时间：
2020-10
影响因子：
6.3
通讯作者：
M. Biggart;J. Stocker;R. Doherty;O. Wild;D. Carruthers;S. Grimmond;Yiqun Han;P. Fu;S. Kotthaus
中科院分区：
文献类型：
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作者：
M. Biggart;J. Stocker;R. Doherty;O. Wild;D. Carruthers;S. Grimmond;Yiqun Han;P. Fu;S. Kotthaus
摘要。北京城乡近地表温差的时空特征，即冠层城市热岛（UHI），对未来城市气候管理具有重要意义。本文研究了2016年冬季和2017年夏季北京地区近地表气温在邻域尺度分辨率（~ 100 m）下的变化。我们使用ADMS-Urban模型的城市气候分量，利用来自当地气候区分类和OpenStreetMap土地利用信息的地表参数进行模拟。通过敏感性模拟，量化了地表性质和人为热排放对北京热岛指数时间变化的相对影响。在中国特大城市大气污染与人类健康（APHH-China）运动期间，北京中心（大气物理研究所）和农村地区（平谷）之间测量的热岛强度在两个季节的~ 4.5°C的夜间达到峰值。在冬季，夜间热岛以人为热排放为主，但被模式低估。更高分辨率的人为热排放可以捕捉局部源（如住宅建筑和邻近的主要道路）的影响。在夏季，夜间热岛强度被低估，特别是在热浪期间。无法完全复制储存在城市结构中的热量的长期释放可能解释了这一点。夏季观测到的白天负热岛强度在北京中心地区地表湿度增加时更容易被捕获。然而，在城市湿度较低的情景下，模拟气温与卫星获取的地表温度之间的空间相关性更强。这一结果表明，城市气象站的近地面气温可能受到精细尺度绿地的影响，而这些绿地是现有土地覆盖数据无法解决的，并表明了与冠层平流相关的地表和空气温度之间的预期差异。本研究为今后北京及其他特大城市热相关健康风险研究和城市热岛缓解策略的研究奠定了基础。
Abstract. Information on the spatiotemporal characteristics of Beijing's urban-rural near-surface air temperature difference, known as the canopy layer urban heat island (UHI), is important for future urban climate management strategies. This paper investigates the variation of near-surface air temperatures within Beijing at a neighbourhood-scale resolution (~ 100 m) during winter 2016 and summer 2017. We perform simulations using the urban climate component of the ADMS-Urban model with land surface parameters derived from both Local Climate Zone classifications and OpenStreetMap land use information. Through sensitivity simulations, the relative impacts of surface properties and anthropogenic heat emissions on the temporal variation of Beijing's UHI are quantified. Measured UHI intensities between central Beijing (Institute of Atmospheric Physics) and a rural site (Pinggu) during the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-China) campaigns, peak during the evening at ~ 4.5 °C in both seasons. In winter, the nocturnal UHI is dominated by anthropogenic heat emissions but is underestimated by the model. Higher resolution anthropogenic heat emissions may capture the effects of local sources (e.g. residential buildings and adjacent major roads). In summer, evening UHI intensities are underestimated, especially during heatwaves. The inability to fully replicate the prolonged release of heat stored in the urban fabric may explain this. Observed negative daytime UHI intensities in summer are more successfully captured when surface moisture levels in central Beijing are increased. However, the spatial correlation between simulated air temperatures and satellite-derived land surface temperatures is stronger with a lower urban moisture scenario. This result suggests that near-surface air temperatures at the urban meteorological site are likely influenced by fine-scale green spaces that are unresolved by the available land cover data and demonstrates the expected differences between surface and air temperatures related to canopy layer advection. This study lays the foundations for future studies of heat-related health risks and UHI mitigation strategies across Beijing and other megacities.