SOCIO-ECONOMIC VULNERABILITY TO URBAN HEAT IN PHOENIX, ARIZONA AND DALLAS, TEXAS DURING JUNE 2020

Abstract. Urban expansion compounded by climate change appears to exacerbate the temperature difference between urban and rural areas. This temperature difference, known as the urban heat island (UHI) effect, results from lack of vegetation, increased impervious surfaces, excess heat released from human activities, and changing radiation and wind dynamics due to urban morphology. UHI has been found to increase heat-related illnesses, and in some instances, mortalities among vulnerable populations. Heat exposure is particularly pertinent in 2020, as stay-at-home orders and higher unemployment rates due to the COVID-19 pandemic have further exposed urban residents to local temperatures. Certain socio-economic groups that are more affected by COVID-19 are disproportionately exposed to high urban temperatures. We investigated the relationships between urban heat island intensity (UHII), normalized difference vegetation index (NDVI), and selected socio-economic factors for Dallas, TX and Phoenix, AZ for June 2020. We used an equal-weighting approach to combine socio-economic factors obtained from 2018 US Census Bureau data to determine socio-economic vulnerability, and used Landsat 8 imagery to derive NDVI and land surface temperature. Pearson’s correlation, hot spot analysis, and Moran’s I tests revealed that socio-economic vulnerability was higher in areas with high urban temperatures and decreased vegetation.