Correlating Urban Sprawl and Urban Heat Island in Dallas and Minneapolis
Source: US Environmental Protection Agency
Urban heat island (UHI) is a temperature phenomenon generally observed in urban areas where urban areas tend to be warmer relative to their surrounding suburban and rural areas. This is because paved and metallic surfaces tend to heat up quicker than green surfaces such as trees and grass, and those paved and metallic surfaces tend to hold heat longer at night, causing air temperatures just above the surface to remain warmer because the heat has not had a chance to escape. In prior research in various areas, this phenomenon has been tied to urban sprawl through various methods.
The goal of this project was to identify a relationship between urban sprawl and urban heat island. Thermal imagery from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor from the Terra EOS Satellite were manipulated to find surface temperature covering areas of the Minneapolis-Saint Paul, MN/WI and Dallas-Fort Worth, TX metropolitan areas. These were compared to land cover data provided by the National Land Cover Database (NLCD) from 2001, 2006, and 2011.
The goal of this project was to identify a relationship between urban sprawl and urban heat island. Thermal imagery from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor from the Terra EOS Satellite were manipulated to find surface temperature covering areas of the Minneapolis-Saint Paul, MN/WI and Dallas-Fort Worth, TX metropolitan areas. These were compared to land cover data provided by the National Land Cover Database (NLCD) from 2001, 2006, and 2011.
UHI (colored fill) compared to impervious surface growth in Collin Co, TX.
The percentage of impervious surface (pavement/buildings) contained within each pixel was also compared to the surface temperature to determine how urban buildup impacts temperature. The data confirms that temperatures in urban areas in general are higher than rural classifications and that UHI has increased in size and amplitude as urban sprawl increased. There were some anomalies that are discussed and some hypotheses on why these anomalies exist. The magnitude of the UHI was measured using percent impervious surface where rural land has less than 15% impervious surface per pixel and urban land has greater than 15% impervious surface. Non-urban land cover was also compared to urban land cover to view trends in UHI magnitude.
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