The subsurface beneath urban areas worldwide is warming up, leading to so-called subsurface urban heat islands. Despite many investigations, limited knowledge is available on the sources (e.g., localized drivers) of subsurface urban heat islands. This paper presents an unprecedented Internet of Things facility to unravel key features characterizing localized drivers of subsurface urban heath islands: a network composed of >150 wireless temperature sensors deployed in surface and subsurface environments across the Chicago Loop district. Through this facility, the study unravels a subsurface urban heat island in the Loop and indicates marked and highly heterogeneous temperatures for localized drivers of such underground climate change. The temperatures of localized drivers characterizing the monitored subsurface heat island can exceed by >25 °C the ground temperature, involving a continuous heat transfer towards this medium. The temperatures of such drivers can further differ by >15 °C across the studied district, not only when different drivers are examined, but also when different locations within the same driver are considered. The identified features of localized drivers of subsurface urban heat islands arguably characterize many cities worldwide, requiring adequate modeling approaches and uncertainty quantifications in future simulation studies on such pervasive phenomena.

全球城市地区的地下正在变暖，导致所谓的地下城市热岛。尽管进行了许多调查，但关于地下城市热岛的来源（例如，局部驱动因素）的知识有限。本文介绍了一种前所未有的物联网设施，用于揭示地下城市荒地的局部驱动因素的关键特征：一个由 > 150 个无线温度传感器组成的网络，部署在芝加哥卢普区的地表和地下环境中。通过该设施，该研究揭示了 Loop 中的一个地下城市热岛，并为这种地下气候变化的局部驱动因素指明了显着且高度异质的温度。表征监测的地下热岛的局部驱动器的温度可能超过 > 地面温度为 25 °C，涉及向该介质的持续热传递。不仅在检查不同驾驶员时，而且考虑到同一驾驶员内的不同位置时，这些驾驶员的温度在所研究区域内可能进一步相差 >15°C。地下城市热岛的局部驱动因素的确定特征可以说是全球许多城市的特征，在未来对这种普遍现象的模拟研究中需要适当的建模方法和不确定性量化。