Karlsruhe Institute of Technology (KIT), Institute for Applied Geosciences (AGW), Kaiserstr. 12, 76131 Karlsruhe, Germany.
Ingolstadt University of Applied Sciences, Institute of new Energy Systems (InES), Esplanade 10, 85019 Ingolstadt, Germany.
Sci Total Environ. 2017 Apr 15;584-585:145-153. doi: 10.1016/j.scitotenv.2017.01.139. Epub 2017 Jan 29.
Human activity directly influences ambient air, surface and groundwater temperatures. The most prominent phenomenon is the urban heat island effect, which has been investigated particularly in large and densely populated cities. This study explores the anthropogenic impact on the thermal regime not only in selected urban areas, but on a countrywide scale for mean annual temperature datasets in Germany in three different compartments: measured surface air temperature, measured groundwater temperature, and satellite-derived land surface temperature. Taking nighttime lights as an indicator of rural areas, the anthropogenic heat intensity is introduced. It is applicable to each data set and provides the difference between measured local temperature and median rural background temperature. This concept is analogous to the well-established urban heat island intensity, but applicable to each measurement point or pixel of a large, even global, study area. For all three analyzed temperature datasets, anthropogenic heat intensity grows with increasing nighttime lights and declines with increasing vegetation, whereas population density has only minor effects. While surface anthropogenic heat intensity cannot be linked to specific land cover types in the studied resolution (1km×1km) and classification system, both air and groundwater show increased heat intensities for artificial surfaces. Overall, groundwater temperature appears most vulnerable to human activity, albeit the different compartments are partially influenced through unrelated processes; unlike land surface temperature and surface air temperature, groundwater temperatures are elevated in cultivated areas as well. At the surface of Germany, the highest anthropogenic heat intensity with 4.5K is found at an open-pit lignite mine near Jülich, followed by three large cities (Munich, Düsseldorf and Nuremberg) with annual mean anthropogenic heat intensities >4K. Overall, surface anthropogenic heat intensities >0K and therefore urban heat islands are observed in communities down to a population of 5000.
人类活动直接影响环境空气、地表水和地下水温度。最显著的现象是城市热岛效应，该效应已在大型和人口稠密的城市中得到了特别研究。本研究不仅在选定的城市地区，而且在德国全国范围内，针对年平均温度数据集，在三个不同的分区中探索人类活动对热状况的影响：实测地表空气温度、实测地下水温度和卫星衍生的地表温度。利用夜间灯光作为农村地区的指标，引入了人为热强度。它适用于每个数据集，并提供了实测局部温度与农村背景温度中位数之间的差异。这个概念类似于成熟的城市热岛强度概念，但适用于大型甚至全球研究区域的每个测量点或像素。对于所有三个分析的温度数据集，人为热强度随夜间灯光的增加而增加，随植被的增加而减少，而人口密度的影响较小。虽然在研究的分辨率（1km×1km）和分类系统中，无法将地表人为热强度与特定的土地覆盖类型联系起来，但空气和地下水都显示出人为表面的热强度增加。总体而言，尽管地下水温度受到部分不受相关过程影响，但它对人类活动最敏感；与地表空气温度不同，地下水温度在耕地中也会升高。在德国表面，在 Jülich 附近的露天褐煤矿附近发现人为热强度最高，达到 4.5K，其次是三个大城市（慕尼黑、杜塞尔多夫和纽伦堡），年平均人为热强度>4K。总体而言，表面人为热强度>0K，因此在人口为 5000 人的社区中观察到城市热岛。
