Characterization of the subsurface urban heat island and its sources in the Milan city area, Italy

Previati, Alberto; Crosta, Giovanni B.

doi:10.1007/s10040-021-02387-z

Cited by 11 publications

(6 citation statements)

References 30 publications

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“…Studies that report urban underground temperature over time are extremely rare and typically only comprise few years. Especially in studies covering less than five years, extreme temperature rises that locally exceed +2 K dec −1 (per decade) are reported [32,40,43], while also average temperature rises are above +0.5 K dec −1 [23,40,43]. In many places urban temperature rise more than doubles the expected surface warming in response to climate change [22,60].…”

Section: Introductionmentioning

confidence: 99%

The evolution of the geothermal potential of a subsurface urban heat island

Hemmerle

Ferguson

Blum

et al. 2022

Environ. Res. Lett.

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Meeting the rising energy demands of cities is a global challenge. Exploitation of the additional heat in the subsurface associated with the subsurface urban heat island (SUHI) has been proposed to address the heating demands. For the sustainable use of this heat it is crucial to understand how SUHIs evolve. To date, there have been no comprehensive studies showing how temperature anomalies beneath cities change over time scales of decades. Here, we reveal the long-term increase of temperatures in the groundwater beneath Cologne, Germany from 1973 to 2020. The rise in groundwater temperature trails atmospheric temperature rise in the rural areas and exceeds the rise in atmospheric temperature in the urban center. However, the amount of heat that is currently stored each year in the thin shallow aquifer reaches only 1% of the annual heating demand. The majority of the anthropogenic heat passes by the vertical extent of the aquifer or is discharged by the adjacent river. Overall the geothermal resource of the urban ground remains largely underused and heat extraction as well as combined heating and cooling could substantially raise the geothermal potential to supply the city’s demand.

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Section: Introductionmentioning

confidence: 99%

The evolution of the geothermal potential of a subsurface urban heat island

Hemmerle

Ferguson

Blum

et al. 2022

Environ. Res. Lett.

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“…Other studies focus on obtaining data on GWT from satellite data with a designated LST [16]. Many studies based on point measurement data also interpolate data in order to obtain groundwater temperatures for the IOP Publishing doi:10.1088/1755-1315/1189/1/012028 13 analysed areas [22,54,55], with particular emphasis on the Kriging method [18,27,56]. The spatial distribution of the SSUHI phenomenon in the above-mentioned studies is similar to the distribution obtained in Wrocław.…”

Section: Discussionmentioning

confidence: 99%

“…Much research related to SSUHI is aimed at determining the geothermal energy potential for a given urban area [4][5][6], due to the ever-growing demand for energy, as well as the growing awareness of ecology. Identification of Subsurface Urban Heat Island was done both by satellite methods [16,25] and by in-situ measurements [22,26,27]. The conducted research has shown an increase in temperature below the city's surface by 2-8 °C in different parts of the world [26,27].…”

Section: Introductionmentioning

confidence: 99%

“…Identification of Subsurface Urban Heat Island was done both by satellite methods [16,25] and by in-situ measurements [22,26,27]. The conducted research has shown an increase in temperature below the city's surface by 2-8 °C in different parts of the world [26,27]. It has been established that the temperature below the earth's surface is influenced by: solar radiation, air temperature, wind speed, rainfall, shelter, and soil properties [28,29].…”

Section: Introductionmentioning

confidence: 99%

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Study of groundwater temperature spatio-temporal variation in the city of Wroclaw. Preliminary results.

Hajnrych

Blachowski

Worsa-Kozak

2023

IOP Conf. Ser.: Earth Environ. Sci.

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In Wrocław over the past 20 years, the recorded increase in the average ambient air temperature is approx. 0.5 °C. In addition, urbanisation has created a phenomenon called the Urban Heat Island (UHI). The combined effect of the UHI and climate change can influence groundwater temperature by penetrating underground. The phenomenon of elevated groundwater temperatures in urban areas is called the Subsurface Urban Heat Island (SSUHI). This study focuses on the spatial distribution of temperature in shallow aquifers in the city of Wroclaw. The spatial distribution was analysed based on groundwater temperature maps developed with various interpolation techniques. The results of measurements in a network of 65 piezometers conducted in the 2004-2005 hydrological year have been used in this study. The temperatures recorded show seasonal variation with the lowest recorded in February (1.3 °C) and the highest in August (24.5 °C) with the annual average of 13.2 °C. The data has been processed with the Inverse Distance Weighted (IDW), Radial Basis Function (RBF) and Kriging interpolation methods. Furthermore, the cokriging method based on multivariate linear regression models has been used to assess if variable such as distance from the city centre improve the interpolation performance expressed as the lowest RMS error value. It has been established that the Kriging univariate regression model based interpolation method produced the best results (RMS error equal to 1.33 °C) and that the distance from the city centre has improved the accuracy of interpolation.

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“…The best results were obtained using the Ordinary Kriging method. In other studies, interpolation methods based on point measurement data were also used to obtain groundwater temperatures for the analyzed areas [46,47], with particular emphasis on the kriging method [48,49].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Distance between the Measured and Assumed Location of a Point Source of Pollution in Groundwater as a Function of the Variance of the Estimation Error

Kovač,

Šrajbek,

Klišanin

et al. 2023

Hydrology

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The localization of pollution sources is one of the main tasks in environmental engineering. For this paper, models of spatial distribution of nitrate concentration in groundwater were created, and the point of highest concentration was determined. This point represents the assumed location of the pollution source and differs from the actual location, so there is a certain distance between the measured and assumed location. This paper puts forward a new hypothesis that the distance between the measured and the assumed location is a function of the variance of the estimation error. The scientific contribution of this paper is based on the fact that the interaction of statistical and geostatistical methods can locate the dominant point source of pollution or narrow down the search area. The above hypothesis is confirmed by the example of the Varaždin wellfield, which was closed due to an excessively high groundwater nitrate concentration. Seven different interpolation methods were used to create spatial distribution models. Each method provides a different model, a different variance of the estimation error, and estimates of the location of the pollution source. The smallest value of variance of the estimation error of 1.65 was obtained for the minimum curvature interpolation method and the largest value of variance (24.49) was obtained for the kriging with logarithmic variogram. Our results show a nonlinear and monotonic relationship between the distance and the variance of the estimation error, so logarithmic and rational quadratic models were fitted to the scatter point data. The models were linearized, a t-test was performed, and the results show that the models can be considered reliable, which is confirmed by the values of the coefficients of determination of the linearized models, which are around 0.50. The obtained results can be used in planning additional research work to determine the measured location of the pollution source. The research methodology we used is universal and can be applied to other locations where high concentrations of certain contaminants have been detected in groundwater in alluvial aquifers.

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Characterization of the subsurface urban heat island and its sources in the Milan city area, Italy

Cited by 11 publications

References 30 publications

The evolution of the geothermal potential of a subsurface urban heat island

The evolution of the geothermal potential of a subsurface urban heat island

Study of groundwater temperature spatio-temporal variation in the city of Wroclaw. Preliminary results.

Analysis of the Distance between the Measured and Assumed Location of a Point Source of Pollution in Groundwater as a Function of the Variance of the Estimation Error

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