Multi-scale Investigation of Principal Heat Transport Processes in Subsurface Urban Heat Islands

由于人口增长和城市化，城市地区的空气温度显着升高，这就是所谓的城市热岛效应（UHI）。在较小的程度上，研究一直致力于对地下的热影响。随着城市的发展，城市浅层地下温度缓慢上升，导致地下也出现大规模的热异常。现在，这些地下超声波是福还是祸？一方面，地面温度升高可能会促进地下水中病原体的生长。另一方面，这些含水层中的热量很有可能满足城市地区的能源需求和/或储存，利用地热泵系统将其用于空间供暖或制冷。为了利用城市含水层的这种潜力，必须全面了解地下城市热岛的主要热传输过程。因此，本研究项目的主要目标是检查地下UHIs的强度，并量化下面的所有主要热通量。作为研究地点，我们选择了两个城市，苏黎世和卡尔斯鲁厄，能够区分特定地点和普遍有效的结果。这两个当地伙伴的合作项目还将受益于他们在实地调查和模拟方面的互补专长。该方法框架具有创新性，采用多尺度监测战略，在受灾害影响的环境中进行基于过程的分析和数值模拟，并采用地球物理/水文地质、统计、工程和遥感技术。

As a result of population growth and urbanization, air temperatures in urban regions are significantly elevated, which is known as the so-called Urban Heat Island (UHI) effect. To a lesser extent, research has been dedicated to the thermal impact on the subsurface. The temperature in the shallow urban subsurface slowly increases with urban development, leading to large-scale thermal anomalies underground as well. Now, are these subsurface UHIs a blessing or a curse? On the one hand, elevated ground temperatures might promote the growth of pathogens in groundwater. On the other hand, the amount of heat available in such aquifers offers a great potential to cover energy demands and/or storages in urban areas using it for space heating or cooling by means of geothermal heat pump systems. To take advantage of this potential of urban aquifers, the principal heat transport processes in the subsurface urban heat islands have to be comprehensively understood. Hence, the main objective of this research project is to examine the intensity of subsurface UHIs and to quantify all dominant heat fluxes beneath. As study sites, we selected the two cities, Zurich and Karlsruhe, to be able to distinguish between site-specific and universally valid findings. The collaborative project of the two local partners will also benefit from their complementary expertise in field investigation and simulation. The methodological framework is innovative, uses a multi-scale monitoring strategy and process-based analytical and numerical simulations in anthropogenically influenced environments, together with geophysical/hydrogeological, statistical, engineering and remote sensing techniques.