A relação entre ilhas de calor urbana superficial, ocupação do solo e desconforto térmico : um estudo em João Pessoa

Abstract

Rapid urbanization and population growth impact land use and land cover changes, leading to deforestation and the replacement of green areas with impervious surfaces, which exacerbates the effects of climate change. Therefore, understanding the impacts caused by urbanization is of great interest to the academic community and urban managers, as it contributes to understanding local climate and mitigating urban heat islands (UHI). The study evaluated the spatiotemporal variability between the years 2013, 2016, 2019, and 2022 of land surface temperature (LST, °C), normalized difference vegetation index (NDVI), normalized difference built-up index (NDBI), and building index (BU), followed by the local dynamics of land use and occupation through Landsat series images covering the city of João Pessoa, Paraíba. In addition, air temperature (T_ar, °C) and relative humidity (UR, %) data from two meteorological stations of the National Institute of Meteorology (INMET) were used to analyze the Thom Discomfort Index (TDI). The results show that deforestation and the loss of green areas, along with urban area growth, contribute to thermal increase and the consequent formation of urban heat islands in the city of João Pessoa. These areas exhibited a land surface temperature of up to 37ºC in 2022, with average temperatures ranging from 25.48ºC (2013), 27.70ºC (2016), 28.38ºC (2019), and 29.54ºC (2022), according to the annual analysis. Regarding NDVI, the average values showed a decrease over the studied period, indicating vegetation loss: 2013 (max: 0.4427, mean: 0.1983), 2016 (max: 0.3948, mean: 0.1760), 2019 (max: 0.3890, mean: 0.1662), and 2022 (max: 0.3876, mean: 0.1277). The BU analysis indicated a significant expansion of built-up areas, with average values increasing from -0.3103 in 2013 to -0.2028 in 2022, reinforcing the correlation between urban growth and thermal increase. João Pessoa was categorized as "uncomfortable," where the TDI was considered partially comfortable (24ºC ≤ TDI ≤ 26.0ºC) in all the analyzed years. The population of João Pessoa has been facing conditions close to thermal discomfort. In summary, João Pessoa requires mitigating and preventive strategies to ensure the health and quality of life of its population.