Assessment of urban heat islands and thermal discomfort in the Amazonia biome in Brazil: A case study of Manaus city

The urban heat island (UHI) is an important phenomenon due to its direct and indirect impacts on the health of the population residing in urban environments. Very few studies have been conducted on the relationships between UHI and outdoor thermal comfort in the Amazonia biome. In this work, we analyzed the behavior of hourly variability of the UHI, heat index (HI), thermal discomfort, and Land Surface Temperature (LST) in Manaus (Brazil). The novelty of the study is to assess the degree of alteration of the UHI with changes in vegetation cover in the Amazon biome. Temperature and air humidity data were collected from six weather stations from July 2013 to July 2014. In addition, satellite images of the TM and OLI/TIRS sensors onboard the Landsat 5 and Landsat 8 satellites for the years 1987, 1998, 2007, and 2015 were used. The intensity of the UHI increased during the analyzed period. The weather stations located in the urban area had temperatures above 30.0 °C, while the temperatures in the rural area ranged from 25.0 to 26.5 °C. As a direct implication of the results found, it is noted that in Manaus, the UHI can reduce thermal comfort in urban spaces, directly impacting people's quality of life and health. The periods with the least amount of precipitation in the city (August and September) can generate thermal discomfort inside houses during the night period, meaning an increase in the number of hours in which people are exposed to heat.