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Urban Heat Island Effect
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13 Articles

Effects of Urban and Surface Proceses on Surface and Lower Troposphere Temperature Trends

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This important paper gives evidence of strong influences of urban activity and other surface processes on measured temperature trends in both the surface dataset by the Climate Research Unit (CRU) and the satellite lower troposphere datasets. The gridded emissions of CO2 is used as a proxy of urbanization. The analysis is done by spatial-thresholding and binning techniques. The analysis finds that surface and satellite-measured temperature trends are higher in the vicinity of industrialized region while this is not found in climate model simulations. Since 1979, non-GHG anthropogenic processes have contributed significantly to surface temperature changes. The land temperature trend is around 170% of the trend where there is little industrialization. The trends in winter are 30% - 40% higher than in summer and spring.

Urban Heat Island Accounts For Half Of Climate Warming In China

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The study shows that about 50% of the recorded warming of China since the 1940’s is due to uncorrected urbanization bias. The near-surface temperature records show that China warmed by about 0.8 °C from 1950 to 2010. The study used the divergence between the minimum (Tmin) and maximum (Tmax) temperatures since the 1940s to estimate the urban heat island effect (UHIE). Atmospheric boundary layer physics predict much higher UHI effect during the night at Tmin than at the daytime at Tmax. The regions in China with the largest Tmin-Tmax divergence are also the most populated, thus the temperature warming is strongly affected by UHI. The actual warming divergence of the Tmin-Tmax over China, 1950-2010, was 4.4 time the average climate model prediction of Tmin-Tmax. Climate models incorrectly attribute this same warming to anthropogenic forcing.

Urban Heat Island Effect in China; Early and Current 20th Century

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This paper by Soon et al 2015 found that temperatures in rural China in the 1940s were higher than at the present. The mostly rural stations had the highest temperatures in the 1940s, and the most urbanized stations had the warmest recent period. The paper found that the homogenizing algorithms that are supposed to remove the UHI effect from the records actually blends the effect over all stations, which increases the temperatures of the least urban records.

The Impacts of Urban Heat Islands in the Spanish Mediterranean

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This paper investigated the urban heat island effect (UHIE) in the Spanish Mediterranean over the 1950–2013 period. The scientists found most of the temperature rise of urban stations occurred in the minimum temperatures, an indication of the UHIE. Satellite-based AVHRR infrared imagery was used to study the urbanization effects from 2001 to 2014. The abstract says “The results obtained have shown both the nature of the [UHIE] phenomenon and its significant magnitude. This magnitude could account for between 70 and 80% of the recorded warming trend in Western Mediterranean cities. Therefore, failure to take this process into account might seriously bias any analysis of regional thermal evolution, the main aim of this study and an aim that equally affects the hypothesis of global climate change.”

National Heat Island: The Effect of Anthropogenic Heat Output on Climate Change

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This study investigates the urban heat island effect (UHIE) on a national scale. It compared the national energy consumption (which is converted to heat) to average national temperatures for the United Kingdom and Japan. Strong correlations are found between energy consumption and temperatures above or below global background levels. In the U.K. for example, temperatures correlate to energy consumption with r2 = 0.89, which is very much greater than the correlation to the CMIP5 climate models used in the last IPCC report of only r2 = 0.10. The abstract says “It is clear that the fluctuation in [temperature] are better explained by energy consumption than by present climate models.

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