Avaliação do fenômeno ilha de calor urbana nas Capitais Nordestinas a partir dos dados do Satélite Sentinel – 3 SLSTR

Abstract

The alteration of the natural space by built-up areas, causes damage to cities, since the materials used in the constructions absorb and retain more energy from the sun than nonurbanized surfaces, such as vegetation, water bodies and others, and this higher temperature retention is a means of causing the phenomenon of the Urban Heat Island (ICU), where it can be understood as the difference in air temperature within the urban area and its surrounding areas. Therefore, it is common to have many works on the subject in cities around the world, however, these studies focus only on a single location where the definition of urban and rural areas are adapted for each case study. However, there is no concrete methodology to define what is a non-urban area and the appropriate selection of this area is of fundamental importance for the estimation of the Urban Heat Island with greater accuracy. Therefore, thinking about this problem, this work proposes to use the methodology proposed by Sobrino et al. 2020, on the determination of urban and non-urban areas in a more objective way and to improve the accuracy of detection of ICU, aimed at the northeast region of Brazil, contributing as a pioneering study in this region, even more taking into account a semiarid climate. Therefore, the objective of the work is to calculate and compare values of urban heat islands in the capital cities of northeastern Brazil. With the surface temperature products obtained from the Sentinel 3 satellite, for the years 2019 and 2020, the Maximum and Average Urban Heat Island, the surroundings of the urban areas were calculated according to the area of each city and the complementary indices to assist in the analysis of the heat island, the thermal field variation index (UFTVI) and the discomfort index (DI). The analyzes of the maximum and average Urban Heat Island, with values between 1.85 and 8.25 and -4.92 and 2.50 K, respectively, allowing to expose the influence of the heat island in the urban area and its surroundings, where most of the capitals analyzed have their central areas with the highest temperature value, which may be due to the analysis of the figures, the urban agglomeration, lack of vegetation and water bodies. UFTVI, with values obtained between 0.010 and 0.040, expresses how terrible the Eco-environmental spaces of the urban area are and DI, with values obtained between 24.61 and 28.89 ºC, expressing the thermal comfort of the population. These indices together allow a better understanding of the phenomenon of the urban heat island on the surface and its consequences on the quality of life of the residents of the cities analyzed.