Análise de microclimas urbanos no centro histórico de Marechal Deodoro, AL

Abstract

The presence of water bodies and topography are prominent aspects in the climatic behavior of urban areas, be they meso or microclimate scales, in coastal and continental areas. The action of the winds on the bodies of waters influences the immediate surroundings, considering the topographic characteristics, occupation of the urban mesh and the atmospheric conditions, making it possible to investigate the changes occurred in the thermo-hygrometric field of a certain place. The study aimed to analyze urban microclimates in the historic center of Marechal Deodoro, located on the banks of the Manguaba Lagoon in the Maceió-Alagoas metropolitan region. The purpose of this study was to characterize the behavior of air temperature and absolute air humidity along a bounded transect in the urban core of the city, considering local topography. In order to do so, the methodological procedures adopted began with the survey of the geological and geoenvironmental characteristics of the municipality, followed by the study area and demarcation of the seven moving points along a transect bounded in the East-West direction, with initial point in the lagoon, entering the continent. In this way, it was possible to obtain points located in different altimetric heights, considering the local topographic profile, and at different distances in relation to the water body. Once the moving points were defined, campaigns were carried out to record climatic data - air temperature, relative humidity and wind speed - on nine consecutive days, with clear sky and calm air conditions. Relative air humidity records were converted to absolute humidity for better hygrometric behavior analysis. The results of the research allowed to verify that the points with greater construction density tend to present the highest air temperatures throughout the day. The areas in which the points are close to the bodies of water, highlights the entrapment of the heat, which raises the temperature of the air during the nocturnal period. And in Tenman Osman de Carvalho Square, where it has the highest topographic quota and the presence of green areas, tend to the lowest values of temperature and absolute humidity of the air. It was also observed that in the night period, the air velocity is reduced in relation to the morning and evening periods, favoring the difference in air temperature between the points. This fact was confirmed by the analysis of the dendograms, in which the points along the transect were grouped according to the similarity of their anthropic and natural characteristics, where the dendogram confirmed the points PM2 and PM3 located in the highest topographic dimensions of the relief under analysis 36 m and 38 m, respectively, presented the lowest air temperatures and absolute air humidity. The proximity to the water bodies was a prominent factor in the results of the clusters, where the dendogram presented the points PM1, PM6 and PM7 as the points of higher temperature and absoulta humidity of the air in the three periods and days of data records. Thus, the study suggests that the urban conformation and the processes of development of the city should consider the use and occupation of the soil, the presence of vegetation and bodies of water influence in the microclimatic determination.