Karlsruhe Institute of Technology (KIT), Institute for Applied Geosciences (AGW), Kaiserstr. 12, 76131 Karlsruhe, Germany.
Sci Total Environ. 2013 Jan 1;442:123-33. doi: 10.1016/j.scitotenv.2012.10.043. Epub 2012 Nov 22.
Little is known about the intensity and extension of subsurface urban heat islands (UHI), and the individual role of the driving factors has not been revealed either. In this study, we compare groundwater temperatures in shallow aquifers beneath six German cities of different size (Berlin, Munich, Cologne, Frankfurt, Karlsruhe and Darmstadt). It is revealed that hotspots of up to +20K often exist, which stem from very local heat sources, such as insufficiently insulated power plants, landfills or open geothermal systems. When visualizing the regional conditions in isotherm maps, mostly a concentric picture is found with the highest temperatures in the city centers. This reflects the long-term accumulation of thermal energy over several centuries and the interplay of various factors, particularly in heat loss from basements, elevated ground surface temperatures (GST) and subsurface infrastructure. As a primary indicator to quantify and compare large-scale UHI intensity the 10-90%-quantile range UHII(10-90) of the temperature distribution is introduced. The latter reveals, in comparison to annual atmospheric UHI intensities, an even more pronounced heating of the shallow subsurface.
关于地下城市热岛 (UHI) 的强度和范围，人们知之甚少，其驱动因素的个体作用也尚未揭示。在这项研究中，我们比较了德国六个不同规模城市（柏林、慕尼黑、科隆、法兰克福、卡尔斯鲁厄和达姆施塔特）浅层含水层中的地下水温度。结果表明，经常存在高达+20K 的热点，这些热点源于非常局部的热源，如隔热不足的发电厂、垃圾填埋场或开放的地热系统。当在等温线地图上可视化区域条件时，通常会发现以市中心的最高温度为中心的同心图。这反映了几个世纪以来热能的长期积累以及各种因素的相互作用，特别是在地下室的热损失、地面温度升高 (GST) 和地下基础设施方面。作为量化和比较大规模 UHI 强度的主要指标，引入了温度分布的 10-90%-分位数范围 UHII(10-90)。后者与年度大气 UHI 强度相比，浅层地下的加热更为明显。
