Identification of the urban heat islands phenomenon in a small city: the study case of Três Rios/RJ, Brazil

Abstract

The phenomenon of urban heat islands (UHIs) is caused by an increase in temperatures in a given urban area as a result of human activities and is usually studied in medium and large cities. This study aimed to verify if the phenomenon of UHIs occurs in the city of Três Rios, RJ, a small-sized town. In this study, a mobile measurement transect was performed considering preestablished data collection points/stations. Five points were selected, including a rural area, an urban park within the city (Parque Natural Municipal), and three points within the urbanized area. The equipment used was the Brunton®/ADC PRO handheld weather station. The data collection period ranged from September 2018 to July 2019, which included the four seasons of the year. Measurements were taken at 6:00, 12:00, 15:00, 18:00, and 21:00 in alternate days during the study period. Considering the temperature measurements, two different indicators of thermal variability were used. Strong magnitude heat islands were detected taking into consideration the relevant variation of maximum temperatures observed in the urban area when compared to the rural area. The results point out that the most affected population are the ones located within urban areas, mostly individuals under socioeconomic vulnerability. The results obtained can be used as support for the development of strategies to minimize the thermal discomfort to populations exposed to the influence of higher magnitude UHIs.