Linking Surface Urban Heat Islands with Groundwater Temperatures (Abstract, Susanne A. Benz, Peter Bayer, Frank M. Goettsche, Folke S. Olesen, and Philipp Blum, Environ. Sci. Technol., Nov. 23, 2015)
Also discussed here: Satellites find sustainable energy in cities (Science Daily, Dec. 18, 2015)
Today we review research that bridges the well studied, (above ground) urban heat island with the urban ground water using satellite-derived temperatures and urban characteristics, such as population density and the number of cellars found in many older cities. This approach tested in Germany, found a spatial correlation of up to 80 % between the above and below ground heat islands and offers the potential of maximizing the potential for using warmer ground water in cities as an energy source for different cities over a large area. This in turn would help to ease the use of carbon fuels otherwise needed to warm urban buildings in winter.
“Temperature anomalies may contribute to regional air pollution and an increased mortality during hot spells in summer. Increased groundwater temperatures influence underground ecosystems and may favor growth of pathogens in groundwater.”
“Energy from close-to-surface groundwater aquifers may be used for heating in winter and cooling in summer with the help of geothermal or groundwater heat pumps. If this geothermal potential would be used, part of the growing energy consumption of cities might be covered. This would reduce emission of greenhouse gases and, thus, counteract global warming"
“Surface and underground heat islands are connected mainly by thermal conduction. So far, research has studied the individual heat islands separately from each other, such that little is known about interactions and relationships between above-ground and underground temperatures”
“The researchers of KIT [Karlsruhe Institute of Technology.] and ETH compared above-ground and underground heat islands in the four cities of Berlin, Munich, Cologne, and Karlsruhe. They found a spatial correlation of up to 80%”
“satellite-measured surface temperature alone is not sufficient to reliably estimate groundwater temperature. For this reason, the scientists also considered population density and cellar temperature.”