Mudanças no ciclo anual de precipitação e temperatura no território brasileiro: regionalização e análise de variação entre períodos climatológicos
Data
2024-05-21
Autores
Domingues, Daniel Araújo 
Orientadores
Martins, Fernando Ramos
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
O Brasil é um país de dimensões continentais que se expande pelo centro e pela costa leste da América do Sul, abrangendo relevos e biomas distintos; por consequência, uma diversidade de regimes climáticos atua em seu território. Este estudo investigou uma regionalização do território brasileiro baseada na similaridade de comportamento climatológico de precipitação acumulada e temperatura média mensal. Foram usadas normais climatológicas de observações obtidas de estações do INMET, formando grupos e subgrupos de acordo com o regime de chuva e temperatura dos períodos climatológicos mais recentes de 1961 a 1990 e de 1991 a 2020. Num segundo momento, foi realizada uma análise de variação de ambas as variáveis na granularidade de estação e de região com base no agrupamento aqui criado. Por fim, a mesma análise foi efetuada para um recorte de estações litorâneas ao longo da costa brasileira, acrescidas as variáveis de temperatura mínima, temperatura máxima e a amplitude térmica mensal em cada período climatológico. O resultado foi a regionalização do País em 4 grandes áreas para precipitação acumulada e para temperatura média baseada na sazonalidade, sendo cada área com 2 sub-regiões de acordo com a intensidade. Com relação à precipitação, detectou-se aumento no volume no Rio Grande do Sul e diminuição no Nordeste e no Sudeste do País, bem como no leste da região Centro-Oeste. Na média, a costa nordestina teve uma queda de 21% em abril e um aumento de 12% em junho, com localidades registrando pico de -57% e +72%, respectivamente. Duas estações na região Nordeste apontaram redução de chuva com significância estatística. Nas regiões Sudeste e Centro-Oeste (e áreas vizinhas na região Norte, Nordeste e Sul), houve localidade que atingiu +16% em março e outra -18% em outubro; apesar de época de estiagem (pouca chuva), estações do estado do Tocantins registraram variação proporcional no meio do ano chegando a +300% no mês de maio. No Rio Grande do Sul, com maior oscilação média dentro da intensidade esperada ao longo do ano, observou-se +41% em abril, seguido de queda até 21% em agosto e depois um forte pico com média de +50% em outubro; o estado apresentou ainda duas localidades com variação de precipitação com significância estatística. Na costa, o estudo sugeriu queda na precipitação no segundo semestre nas regiões Norte e Nordeste, opondo-se a um aumento de precipitação no primeiro semestre nas regiões Sudeste e Sul. Quando se trata de temperatura, mais de 90% das estações registraram acréscimo de pelo menos 0,5 °C e houve aumento médio de 0,8 °C no Brasil, com destaque aos meses de dezembro a abril com variação entre 0,8 °C e 0,9 °C na média. A área com maior diferença na mediana anual foi o Centro-Norte, entre o Nordeste e o Norte do País. Essa região apresentou uma variação em forma de senoide entre 0,86 °C e 1,39° C na média. Como em camadas, cada região/grupo que se distancia do Centro-Norte, o aumento de temperatura média torna-se mais suave. A costa leste (última camada) brasileira e a região Sul apresentaram um piso de aumento médio de 0,24 °C em julho e pico de 0,9 °C em abril. As mudanças constatadas favorecem a ocorrência de cenários extremos: mais períodos de seca em áreas com pouca chuva, mais chuva em meses e regiões com maior precipitação; mais frio em regiões frias no inverno e mais calor em regiões quentes no verão.
Brazil is a country of continental dimensions that spans the center and east coast of South America, encompassing distinct reliefs and biomes; as a result, a diversity of climatic regimes operate in its territory. This study investigated a regionalization of the Brazilian territory based on the similarity of the climatological behaviour of accumulated precipitation and average monthly temperature. Climatological normal observations from INMET stations were used, forming groups and subgroups according to the rainfall and temperature regime of the most recent climatological periods from 1961 to 1990 and 1991 to 2020. Secondly, an analysis of the variation of both variables was carried out at the granularity of station and region based on the grouping created here. Finally, the same analysis was carried out for a selection of coastal stations along the Brazilian coast, adding the variables of minimum temperature, maximum temperature and monthly temperature range for each climatological period. The result was the regionalization of the country into 4 large areas for accumulated precipitation and average temperature based on seasonality, with each area having 2 sub-regions according to intensity. With regard to precipitation, an increase in volume was detected in the Rio Grande do Sul and a decrease in the Northeast and Southeast of the country, as well as in the east of the Midwest. On average, the northeastern coast saw a 21% drop in April and a 12% increase in June, with locations registering peaks of -57% and +72%, respectively. Two stations in the Northeast showed a statistically significant reduction in rainfall. In the Southeast and Mid-West regions (and neighboring areas in the North, Northeast and South), there was a location that reached +16% in March and another -18% in October; despite the dry season (little rain), stations in the state of Tocantins recorded a proportional variation in the middle of the year, reaching +300% in May. In Rio Grande do Sul, with a greater average oscillation within the expected intensity throughout the year, there was +41% in April, followed by a drop of up to 21% in August and then a strong peak with an average of +50% in October; the state also had two locations with statistically significant rainfall variation. On the coast, the study suggested a drop in precipitation in the second half of the year in the North and Northeast, as opposed to an increase in precipitation in the first half in the Southeast and South. When it comes to temperature, more than 90% of the stations recorded an increase of at least 0.5 °C and there was an average increase of 0.8 °C in Brazil, with the months of December to April standing out with a variation between 0.8 °C and 0.9 °C on average. The area with the greatest difference in the annual median was the Center North, between the Northeast and the North of the country. This region showed a sinusoidal variation between 0.86 °C and 1.39 °C on average. As in layers, each region/group that moves away from the North Center, the increase in average temperature becomes smoother. The east coast (last layer) of Brazil and the south showed an average increase of 0.24 °C in July and a peak of 0.9 °C in April. The changes observed favor the occurrence of extreme scenarios: more periods of drought in areas with little rain, more rain in months and regions with more precipitation; colder in cold regions in winter and hotter in hot regions in summer.
Brazil is a country of continental dimensions that spans the center and east coast of South America, encompassing distinct reliefs and biomes; as a result, a diversity of climatic regimes operate in its territory. This study investigated a regionalization of the Brazilian territory based on the similarity of the climatological behaviour of accumulated precipitation and average monthly temperature. Climatological normal observations from INMET stations were used, forming groups and subgroups according to the rainfall and temperature regime of the most recent climatological periods from 1961 to 1990 and 1991 to 2020. Secondly, an analysis of the variation of both variables was carried out at the granularity of station and region based on the grouping created here. Finally, the same analysis was carried out for a selection of coastal stations along the Brazilian coast, adding the variables of minimum temperature, maximum temperature and monthly temperature range for each climatological period. The result was the regionalization of the country into 4 large areas for accumulated precipitation and average temperature based on seasonality, with each area having 2 sub-regions according to intensity. With regard to precipitation, an increase in volume was detected in the Rio Grande do Sul and a decrease in the Northeast and Southeast of the country, as well as in the east of the Midwest. On average, the northeastern coast saw a 21% drop in April and a 12% increase in June, with locations registering peaks of -57% and +72%, respectively. Two stations in the Northeast showed a statistically significant reduction in rainfall. In the Southeast and Mid-West regions (and neighboring areas in the North, Northeast and South), there was a location that reached +16% in March and another -18% in October; despite the dry season (little rain), stations in the state of Tocantins recorded a proportional variation in the middle of the year, reaching +300% in May. In Rio Grande do Sul, with a greater average oscillation within the expected intensity throughout the year, there was +41% in April, followed by a drop of up to 21% in August and then a strong peak with an average of +50% in October; the state also had two locations with statistically significant rainfall variation. On the coast, the study suggested a drop in precipitation in the second half of the year in the North and Northeast, as opposed to an increase in precipitation in the first half in the Southeast and South. When it comes to temperature, more than 90% of the stations recorded an increase of at least 0.5 °C and there was an average increase of 0.8 °C in Brazil, with the months of December to April standing out with a variation between 0.8 °C and 0.9 °C on average. The area with the greatest difference in the annual median was the Center North, between the Northeast and the North of the country. This region showed a sinusoidal variation between 0.86 °C and 1.39 °C on average. As in layers, each region/group that moves away from the North Center, the increase in average temperature becomes smoother. The east coast (last layer) of Brazil and the south showed an average increase of 0.24 °C in July and a peak of 0.9 °C in April. The changes observed favor the occurrence of extreme scenarios: more periods of drought in areas with little rain, more rain in months and regions with more precipitation; colder in cold regions in winter and hotter in hot regions in summer.
Descrição
Citação
DOMINGUES, Daniel Araújo. Mudanças no ciclo anual de precipitação e temperatura no território brasileiro: regionalização e análise de variação entre períodos climatológicos. 2024. 182 f. Dissertação (Mestrado Interdisciplinar em Ciência e Tecnologia do Mar) - Universidade Federal de São Paulo, Instituto do Mar, Santos, 2024.