O clima urbano em ambiente tropical: análise do perfil térmico de Rondonópolis-MT
Carregando...
Arquivos
Data
2021-10-29
Autores
Gomes, Washington Paulo
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
As populações que vivem nas cidades tropicais são acometidas por elevadas temperaturas que ocorrem naturalmente devido a sua posição latitudinal e apresentam maior vulnerabilidade aos eventos extremos de calor. Como os ambientes urbanos, que estão em constante crescimento, são mais quentes que os ambientes não urbanizados, os impactos na saúde humana são cada vez mais notados. A intensificação desse processo e o grau de transformação do espaço urbano está associado ao aumento do ritmo de crescimento dos centros urbanos e a falta de planejamento urbano adequado para gerenciar a expansão das cidades e a ocupação das áreas mais apropriadas para o assentamento humano. O espaço urbano possui uma estrutura complexa e as superfícies apresentam diferentes capacidades de absorção da radiação solar e no armazenamento de calor. Essas características contribuem para o maior armazenamento de calor durante o dia, configurando em diferenças térmicas, sobretudo após o pôr do sol, em comparação com o ambiente rural que apresenta rápido resfriamento. Até o momento, poucos estudos analisaram os impactos econômicos, sociais e ambientais no contexto das cidades tropicais de médio porte, onde as aglomerações urbanas também apresentam transformações na paisagem natural. O município de Rondonópolis está localizado na porção sudeste do estado de Mato Grosso, com população de 236.042 habitantes (IBGE, 2020) e está inserida no contexto das cidades médias brasileiras. A extensão territorial do estado de Mato Grosso, localizado na porção central da América do Sul, impõe características específicas dos climas continentais das latitudes intertropicais. A hipótese pressupõe que uma cidade de porte médio localizada no ambiente tropical continental responde de forma diferenciada aos sistemas atmosféricos atuantes e possui especificidades no sítio e na produção do espaço urbano que comprovam a formação de um clima urbano específico. Nesta perspectiva, levando em consideração as particularidades climáticas e as respostas térmicas no contexto da espacialização das ilhas de calor, o objetivo central da tese é analisar o clima urbano da cidade de Rondonópolis-MT, com ênfase no subsistema termodinâmico, apresentando as intensidades das ilhas de calor de acordo com as características da superfície. Para tanto, os procedimentos metodológicos adotados se basearam na coleta de dados por medidas móveis, pontos fixos, imagens de satélites e modelagem climática. Os transectos móveis para a coleta de dados de temperatura foram realizados às 21h, em quatro episódios, durante os dias 01 e 17 de junho, 20 de julho e 05 de setembro de 2020. Para as medidas fixas foram utilizados 11 (onze) sensores distribuídos pela malha urbana e a estação meteorológica automática gerenciada pelo INMET, localizada na Universidade Federal de Rondonópolis, totalizando 12 (doze) pontos de coleta dos dados de temperatura nos meses de julho a dezembro de 2019. As técnicas de sensoriamento remoto foram utilizadas no primeiro momento para identificar as ilhas de calor de superfícies e no segundo momento para realizar a modelagem da ilha de calor urbana, considerando as características de uso e a ocupação da terra. Os resultados apontaram intensidades máximas de até 14ºC nas ilhas de calor de superfícies, 10,5ºC nos transectos móveis, 12,5ºC nos pontos fixos e 11ºC nas modelagens das intensidades das ilhas de calor urbanas, configurando-se em ilhas de calor de muito forte magnitude. A partir da modelagem foi elaborada um mapa térmico da cidade de Rondonópolis-MT, evidenciando as áreas mais quentes. As intensidades das ilhas de calor urbanas estão associadas aos sistemas atmosféricos atuantes, as formas do relevo e ao uso e ocupação da terra, atrelados aos diferentes agentes que produzem o espaço urbano de acordo com os seus interesses.
Populations living in tropical cities are affected by naturally occurring high temperatures due to their latitudinal position and are vulnerable to extreme heat events. As urban environments, which are constantly growing, are warmer than undeveloped environments, impacts on human health are increasingly noticed. The intensification of this process and the degree of transformation of the urban space is associated with the increased pace of growth of urban centers and the lack of adequate urban planning to manage the expansion of cities and the occupation of the most appropriate areas for human settlement. Urban space has a complex structure and surfaces have different capacities for absorbing solar radiation and storing heat. These characteristics contribute to greater heat storage during the day, resulting in thermal differences, especially after sunset, compared to the rural environment, which presents fast cooling. So far, few studies have analyzed the economic, social and environmental impacts in the context of medium-sized tropical cities, where urban agglomerations also present transformations in the natural landscape. The municipality of Rondonópolis is located in the southeastern portion of the state of Mato Grosso, with a population of 236,042 inhabitants (IBGE, 2020) and is inserted in the context of medium-sized Brazilian cities. The territorial extension of the state of Mato Grosso, located in the central portion of South America, imposes specific characteristics of the continental climates of intertropical latitudes. The hypothesis assumes that a medium-sized city located in the continental tropical environment responds in a different way to the active atmospheric systems and has specificities in the site and in the production of urban space that prove the formation of a specific urban climate. In this perspective, considering the climatic particularities and thermal responses in the context of the spatialization of heat islands, the main objective of the thesis is to analyze the urban climate of the city of Rondonópolis-MT, with an emphasis on the thermodynamic subsystem, presenting the intensities of the heat islands according to the surface characteristics. Therefore, the methodological procedures adopted were based on data collection by mobile measurements, fixed points, satellite images and climate modeling. Mobile transects for temperature data collection were performed at 9 pm, in four episodes, during June 1st, June 17th, July 20th and September 5th of 2020. For fixed measurements, 11 (eleven) sensors distributed throughout the urban grid and the automatic meteorological station managed by INMET, located at the Federal University of Rondonópolis, were used, totaling 12 (twelve) temperature data collection points from July to December of 2019. Remote sensing techniques were used in the first moment to identify the surface heat islands and in the second moment to carry out the urban heat island modeling, considering the characteristics of land use and occupation. The results showed maximum intensities of up to 14ºC in surface heat islands, 10.5ºC in mobile transects, 12.5ºC in fixed points and 11ºC in urban heat island intensities modeling, configuring very strong heat islands magnitude. From the modeling, a thermal map of the city of Rondonópolis-MT was elaborated, showing the hottest areas. The intensities of urban heat islands are associated with the active atmospheric systems, the forms of relief and the use and occupation of land, linked to the different agents that produce the urban space according to their interests.
Populations living in tropical cities are affected by naturally occurring high temperatures due to their latitudinal position and are vulnerable to extreme heat events. As urban environments, which are constantly growing, are warmer than undeveloped environments, impacts on human health are increasingly noticed. The intensification of this process and the degree of transformation of the urban space is associated with the increased pace of growth of urban centers and the lack of adequate urban planning to manage the expansion of cities and the occupation of the most appropriate areas for human settlement. Urban space has a complex structure and surfaces have different capacities for absorbing solar radiation and storing heat. These characteristics contribute to greater heat storage during the day, resulting in thermal differences, especially after sunset, compared to the rural environment, which presents fast cooling. So far, few studies have analyzed the economic, social and environmental impacts in the context of medium-sized tropical cities, where urban agglomerations also present transformations in the natural landscape. The municipality of Rondonópolis is located in the southeastern portion of the state of Mato Grosso, with a population of 236,042 inhabitants (IBGE, 2020) and is inserted in the context of medium-sized Brazilian cities. The territorial extension of the state of Mato Grosso, located in the central portion of South America, imposes specific characteristics of the continental climates of intertropical latitudes. The hypothesis assumes that a medium-sized city located in the continental tropical environment responds in a different way to the active atmospheric systems and has specificities in the site and in the production of urban space that prove the formation of a specific urban climate. In this perspective, considering the climatic particularities and thermal responses in the context of the spatialization of heat islands, the main objective of the thesis is to analyze the urban climate of the city of Rondonópolis-MT, with an emphasis on the thermodynamic subsystem, presenting the intensities of the heat islands according to the surface characteristics. Therefore, the methodological procedures adopted were based on data collection by mobile measurements, fixed points, satellite images and climate modeling. Mobile transects for temperature data collection were performed at 9 pm, in four episodes, during June 1st, June 17th, July 20th and September 5th of 2020. For fixed measurements, 11 (eleven) sensors distributed throughout the urban grid and the automatic meteorological station managed by INMET, located at the Federal University of Rondonópolis, were used, totaling 12 (twelve) temperature data collection points from July to December of 2019. Remote sensing techniques were used in the first moment to identify the surface heat islands and in the second moment to carry out the urban heat island modeling, considering the characteristics of land use and occupation. The results showed maximum intensities of up to 14ºC in surface heat islands, 10.5ºC in mobile transects, 12.5ºC in fixed points and 11ºC in urban heat island intensities modeling, configuring very strong heat islands magnitude. From the modeling, a thermal map of the city of Rondonópolis-MT was elaborated, showing the hottest areas. The intensities of urban heat islands are associated with the active atmospheric systems, the forms of relief and the use and occupation of land, linked to the different agents that produce the urban space according to their interests.
Descrição
Palavras-chave
Clima tropical, Clima urbano, Ilhas de calor, Rondonópolis-MT, Mato Grosso, Tropical weather, Urban climate, Heat islands