We investigated the distribution of air temperature (Ta) and the factors affecting it in low-rise areas surrounding an isolated high-rise building during the Japanese winter. The study site was the central part of a regional city in Japan (36°5' N, 140°12' E), lying north-east of the Tokyo metropolitan area. The daytime surface temperature (Ts) in the shade is generally considered to be comparable to Ta; however, according to airborne remote sensing conducted in December 2009 where a multi-spectral scanner was installed on a fixed-wing aircraft, Ts for pavements in the shade of a high-rise building was significantly lower than Ta of sub-urban areas, indicating an influence of cold storage on Ts. Then, we conducted mobile observations using instruments (thermocouple, four component radiometer, and so on) installed on a bicycle in January 2016 to investigate the detailed distribution of Ta and the factors affecting it. The results showed the Ta over the pavements in the shade of the high-rise building was lower than the Ta of sunlit areas in the same urban area by -2 °C and lower than the Ta of sub-urban areas by -1-1.5 °C, although the advection effect was large due to strong winds around the building. In conclusion, a locally lower Ta compared to the surrounding areas can develop during the day in winter, even in spaces that are open to areas beyond the canopy.

中文翻译：

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在日本冬季，围绕高层建筑的城市区域热环境的机载和地面观测。

我们调查了日本冬季期间，在孤立的高层建筑周围的低层区域中，气温（Ta）的分布及其影响因素。研究地点是位于东京都会区东北部的日本区域性城市（北纬36°5'，东经140°12'）的中心部分。通常认为阴影下的白天表面温度（Ts）与Ta相当；但是，根据2009年12月进行的机载遥感技术（在固定翼飞机上安装了多光谱扫描仪），高层建筑阴影中的人行道的Ts明显低于郊区的Ta，冷藏对Ts的影响。然后，我们使用仪器（热电偶，四分量辐射计，等）于2016年1月安装在自行车上，以调查Ta的详细分布及其影响因素。结果表明，高层建筑阴影下的人行道上的Ta比同一城市的日照区的Ta低-2°C，比郊区的Ta低-1-1.5 °C，尽管由于建筑物周围强风对流影响很大。总而言之，冬季白天甚至在向树冠以外区域开放的空间中，都会产生比周围区域低的Ta。结果表明，高层建筑阴影下的人行道上的Ta比同一城市的日照区的Ta低-2°C，比郊区的Ta低-1-1.5 °C，尽管由于建筑物周围强风对流影响很大。总而言之，冬季白天甚至在向树冠以外区域开放的空间中，都会产生比周围区域低的Ta。结果表明，高层建筑阴影下的人行道上的Ta比同一城市的日照区的Ta低-2°C，比郊区的Ta低-1-1.5 °C，尽管由于建筑物周围强风对流影响很大。总而言之，冬季白天甚至在向树冠以外区域开放的空间中，都会产生比周围区域低的Ta。