The Brazilian Journal of Climatology (RBCLima) is an official publication of the Brazilian Association of Climatology - ABClima, a non-profit scientific association. Its objective is to publish unpublished articles produced by researchers and teachers who work in Climatology, Geography, Meteorology, Ecology, Agronomy, Engineering, Architecture and other related areas. In addition to being a vehicle of knowledge and information, it aims at stimulating the scientific production of climatology scholars and disseminating the state of the art in this field of knowledge. Qualis: B1 Geography and A2 Environmental Sciences Knowledge area: Geography Year of foundation: 2005 e-ISSN: 2237-8642 Short title: RBClima E-mail: rbclima2014@gmail.com Unit: ABCLIMA DOI prefix: 10.5380/abclima
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ESTIMATION OF RAINFALL EROSIVITY OF THE CORURIPE RIVER BASIN IN ALAGOAS
The ability of rains to cause erosion is defined as erosivity (R factor). This study contributes to reducing soil loss rates. Thus, with this work, the objective was to determine the rainfall erosivity rates in the Coruripe River basin in Alagoas, through mathematical models. Rainfall data were obtained from SUDENE, SMDRA and SEMARH for 12 municipalities in the basin. The rainfall coefficient was determined and mathematical models were used to estimate the R factor. Data were subjected to regression analysis using a spreadsheet. It is noted that the maximum and minimum erosivity indices are related to the highest and lowest rainfall, respectively. Analyzed correlations showed high coefficients of determination. Therefore, the most critical period for the R factor occurs between April and July, the rainy season. And mathematical models analyzed can be used to estimate this factor in the studied river basin.
Copyright (c) 2025 Julio César Calixto Costa, Rubiana do Nascimento Lira, Cícero Gomes dos Santos, Márcio Aurélio Lins dos Santos, Thaís Rayane Gomes da Silva
Climate change in Maranhão: evolution, trends, and future projections
This research intend to analyze the impacts of climatic changes over a timespan of sixty years of atmospheric components of temperatura and rainfall in the state of Maranhão, allowing some forecastings for a near future. The North and Northeast regions of Brazil have undergone an intense deforestation process, wildfires, and accelerated agricultural expansion, demanding studies to measure how it impacts on overall climate changes and to extrapolate the most probable future scenarios, which could help on current decision making on this issue. Maranhão, due to its unique geographical location, territorial extension, bioma and ecosystem diversity, and its importance in the MATOPIBA context, is a significant and illustrative case study of some trends that have happened in climate changes in the North and Northeast areas of Brazil. Bibliographic researches were carried out and data gathering in government research institutes like INMET, FIOCRUZ and INPE/CPTEC, allowing us to produce maps and statistical graphs that identify climate changes currently under its way. The obtained results shown, in an unambiguous way, that in the last sixty years the average temperature has risen +0,9°C and a decrease in the pluviometric indexes between -250 and 600mm, depending on the focused location. Regarding future scenarios, based on the sampled data from FIOCRUZ and INPE/CPTEC, in the next 25 and 50 years, we got some worrying and terrifying prospects that point to a temperature rise in the order of +5,4°C and a rainfall decrease in the order of -32%, compared to the current climatic parameters, which will have highly negative repercussions for various agricultural and economic activities, with direct consequences on social development.
Copyright (c) 2025 Juarez Mota Pinheiro, Irecer Portela Figueiredo Santos
Dinâmica da precipitação em florestas e áreas de desmatamento durante a estação seca na Amazônia Centro-Leste: um estudo de caso na bacia do Xingu
O regime de precipitação na bacia do Xingu é um aspecto importante do clima regional da Amazônia. Neste artigo, analisamos tendências e eventos extremos de precipitação em áreas florestadas e de desmatamento da bacia do Xingu, na Amazônia oriental. Os dados estimados foram validados utilizando pluviômetros, e métodos estatísticos foram aplicados para avaliar as tendências nos padrões de precipitação e espacializar a inclinação de Sen para fornecer insights para a gestão dos recursos hídricos na região durante a estação seca. A análise emprega testes de correlação Ponto-Bisserial para avaliar a associação entre a cobertura florestal binária (1 para floresta, 0 para não floresta) e diversos índices de precipitação. Todas as estações com teste Mann-Kendall significativo apresentaram diminuição da precipitação, e a maior tendência de redução de precipitação encontrada foi de -0,43 mm por mês para a estação 151003. Os resultados da correlação RPB sugerem que a cobertura florestal está mais fortemente associada à persistência e à intensidade de períodos úmidos do que a eventos extremos isolados de precipitação, lançando luz sobre a interação entre os padrões de precipitação e a dinâmica florestal.
Copyright (c) 2025 Rodrigo Martins Moreira, Bruno César dos Santos
Flow analysis in the Paraíba do Sul river watershed
Understanding the patterns of variations in the hydrological cycle is essential for the efficient management of water resources. In this context, the objective of this study was to analyze the annual maximum, minimum, and mean flows, as well as the main reference flows in the Paraíba do Sul River watershed, identifying trends and patterns that may contribute to a better understanding of the region's water dynamics. For this purpose, data from 12 streamflow gauging stations located in the Alto Paraíba do Sul (São Paulo section - TP), Médio Paraíba do Sul (MP), and Piabanha (PB) regions were analyzed for the period from 1987 to 2023. The data were obtained from the hydrometeorological network managed by the National Water and Basic Sanitation Agency. After verifying data quality, annual averages of maximum, minimum, and mean flows were assessed, along with their trends. Among the 12 stations analyzed, Volta Redonda (MP) and Paraíba do Sul (MP) recorded the highest flow values, with annual maximum flow averages of 782.9 m³/s and 693.3 m³/s, respectively. In trend analysis, it was found that the Santa Branca (TP) station showed statistically significant trends at the 5% level in maximum, minimum, and mean annual flows. Regarding reference flows, the MP region exhibited the highest water availability, with the Volta Redonda (MP) station recording a Q90 value of 401.5 m³/s. On the other hand, the TP and northern PB regions showed the lowest values, with the Fazenda Santa Clara (TP) station standing out with a Q90 of 6.14 m³/s.
Copyright (c) 2025 Douglas da Silva Ferreira, Gildo Rafael de Almeida Santana , Eliane Barbosa Santos
Statistical relationship between Dengue cases in Maceió and climate variability in the Pacific and Atlantic Oceans
Dengue is a systemic disease with viral etiology, and the transmission vector for this disease is the Aedes aegypti mosquito, whose intense proliferation, starting in the 1980s, resulted in explosive epidemics in all Brazilian regions. Therefore, the objective of the work is to carry out an assessment of the relationship between the climate variability of the Pacific and Atlantic Oceans and the occurrence of Dengue in Maceió. For this, precipitation data, monthly data on the number of dengue cases in Maceió, and data from the IOS Index and the Atlantic Dipole were used, with a common data period of 2014-2023. In relation to the variability of the Pacific Ocean, it was identified It is clear that periods of increase in Dengue cases also simultaneously presented records of ENSO occurrence. The coherence analysis between Precipitation and Dengue Cases in Maceió verified that the maximum of the two series occur simultaneously. In relation to the variability of the Atlantic Ocean, it was noticed that in some periods of increase in Dengue cases there were records of the negative phase of the Dipole. In the analysis of coherence between Dengue cases and the Dipole index, it indicated that on the seasonal scale, the maximum number of Dengue cases occurred 20 days after the maximum of the Dipole. In this way, it is suggested that by following and monitoring these climatic indices, and using the Cross Wavelet, can be estimated when the maximum number of Dengue cases will statistically occur in Maceió.
Copyright (c) 2025 Djane Fonseca da Silva, Pedro Fernandes de Souza Neto
Regionalization of reference and real evapotranspiration for the state of Alagoas, Northeastern Brazil
Reference evapotranspiration (ET0) refers to the atmospheric water demand based on a standardized surface (without water restrictions) and actual evapotranspiration (ETr) is the water loss to the atmosphere that actually occurs. The objective of this work is to regionalize and analyze the temporal and spatial variabilities of ET0 and ETr for the state of Alagoas. Monthly ET0 data (1961 to 2019) and ETr data from the MOD16 product (2001 to 2020) were used. Using the data, descriptive statistical, multivariate (Cluster and Silhouette analysis) and Geostatistical (IDW - Inverse Distance Weighting) analyses were applied, respectively, for characterization, identification of homogeneous areas and interpolation for spatial representation. Among the main results, it is worth highlighting that the variations in ETr are greater than ET0. This study defined four subregions for ET0 and ETr, called S1, S2, S3 and S4. ET0 is higher in the western portion of the state of Alagoas (S4) and values ​​decrease towards the eastern portion (S1). On the other hand, the opposite occurs for ETr. The period of highest ET0 occurs between October and March, while the lowest values ​​are recorded between June and July, that is, depending on the availability of energy. ETr is, on average, higher in the rainy season (July) and lower in the dry season (December). Variations in ETr are associated with factors such as uneven distribution of moisture in the soil and local climate conditions (mainly associated with rainfall distribution). It is concluded that this information is essential for the sustainable management of water resources and agricultural planning, especially in semiarid environments.
Copyright (c) 2025 Lucas de Morais Teixeira, Helder José Farias da Silva, Ana Paula Lopes da Silva, Fabrício Daniel dos Santos Silva, Daniele Tôrres Rodrigues, Jean Souza dos Reis , Jório Bezerra Cabral Júnior
Dynamics of cold events in the Pantanal region: a study using reanalysis data from 1981 to 2023
A cold spell (locally known as friagem) is a climatic phenomenon characterized by the intrusion of polar air masses into Brazil's tropical regions, significantly impacting the Pantanal. This study examined the occurrence and variability of cold spells in the region from 1981 to 2023, utilizing ERA5 reanalysis data obtained through Google Engine. Cold spells were identified based on thermal anomalies, specifically considering periods of at least three consecutive days with temperatures falling below the climatological 10th percentile. The results indicate that cold spells predominantly occur between May and September, with greater intensity in June and July. During these events, the maximum temperature drops sharply in the initial days, while the minimum temperature continues to cool persistently. A progressive reduction in precipitation associated with cold spells has been observed over the last four decades, suggesting changes in regional atmospheric circulation. In addition to their impact on climate, cold spells affect biodiversity, agriculture, and human health, potentially increasing mortality rates from respiratory and cardiovascular diseases. This study underscores the necessity for continuous monitoring and enhancement of meteorological forecasts, which contribute to strategies aimed at mitigating environmental and socio-economic impacts in the Pantanal.
Copyright (c) 2025 Raquel de Cássia Ramos, Gabriel Pereira, Emerson Galvani, Francielle da Silva Cardozo, Paula Resende Santos, Shayene Bernardo Dutra
Impact of deforestation at surface temperature and vegetation in the Biological Reserve of Jaru – RO
The Jaru Biological Reserve has been experiencing threats to environmental stability, especially along its edges. This study aimed to assess the relationship between Land Surface Temperature (LST) and the Normalized Difference Vegetation Index (NDVI), based on Landsat 5 and 8 imagery spanning 1992 to 2023. The results showed an 11.77% reduction in native vegetation and an increase of up to 13 °C in LST, with an increasingly negative correlation between LST and NDVI (-0.9004 in 2023). Areas with dense vegetation exhibited lower temperatures, while altered regions experienced significant warming, reflecting the impacts of land-use changes. These findings highlight the importance of LST monitoring and underscore the urgent need for effective management strategies to mitigate anthropogenic pressures on conservation units.
Copyright (c) 2025 Jaina Rodrigues Evangelista, Sara Regiane Tavares Lopes, Lucas Matheus Matos Pacheco Ziles, Graziela Tosini Tejas, João Paulo Assis Gobo
Preservation and restoration of forest fragments: a contribution to promoting climate justice in peripheral urban areas
The territories affected by climate change face a lack of services and urban infrastructure, environmental degradation, various forms of violence, and a scarcity of vegetation, creating a scenario of vulnerability to climate change. Considering that small fragments of green areas still exist in the outskirts, they can become part of the strategy for confronting and mitigating climate extremes in peripheral areas, as illustrated by the experience developed in a fragment of Atlantic Forest in the Água Mineral neighborhood, in the municipality of São Gonçalo–RJ. The objective of this article is to contribute to the expansion of debates and the possible replication of this experience in other territories marked by environmental and climate injustice. The urbanization model can be understood as the intersection between environmental justice and climate justice within the context of Brazilian society and the municipality of São Gonçalo. Climate justice is a right established in several legal instruments, particularly in the 1988 Federal Constitution, and requires an ethical commitment to care and respect for the environment of present generations, with a forward-looking perspective, transforming spaces of climate injustice into safe spaces in the face of climate change. The experience of the Gênesis Environmental Education Center demonstrates how the restoration of an urban forest fragment of the Atlantic Forest becomes a strategy in areas of environmental injustice, serving as an adaptation and mitigation measure that reduces environmental vulnerability in the face of the impacts of climate change.
Copyright (c) 2025 Lourdes Brazil dos Santos Argueta , Samira França Oliveira, Jupira Farias de Oliveira, Carlos César Gonzalez de Luna
Precipitation Variability In Mato Grosso Do Sul, a Space-Time approach and the proposal of a Regional Synthesis
This article presents a spatiotemporal approach to precipitation in the state of Mato Grosso do Sul, using models and statistical techniques to spatialize possible trends related to rainfall variability. Climate variations are analyzed using historical series of meteorological variables, with a focus on rainfall. The objective is to investigate trends in long annual rainfall series (over 30 years) using three rainfall quantification indices: the Rainfall Anomaly Index (RAI) van Rooy (1965), the Pettitt Test (Pettitt, 1979), and the Mann-Kendall Test (Mann, 1945; Kendall, 1975). The results provided a clearer understanding of the trends by subdividing the territory into four climate sectors: Sector S.1 Center-South showed a linear trend of increased rainfall at 10 rainfall stations, while 3 showed a slight decrease; Sector S.2 Center-East showed an increase at 14 stations and a decrease at 10; Sector S.3 West showed a decrease at 12 stations and a slight increase at 2; and finally, Sector S.4 Southwest showed a decrease at 6 stations and an increase at another 6. The analysis demonstrated the complexity of rainfall dynamics in the state, with each sector showing a specific trend. The study highlights the importance of further research into regional and local climatology for the planning and management of water resources and economic activities, such as agriculture, in the face of increasing climate variability.
Copyright (c) 2025 Heverton Schneider, Charlei Aparecido da Silva
Mudanças climáticas e doenças negligenciadas: a epidemia de Dengue na Região Sul do Brasil
A dengue, uma doença negligenciada significativa, está passando por uma rápida escalada e expansão geográfica, particularmente no contexto das mudanças climáticas. O aquecimento global desempenha um papel crítico no aumento das epidemias de dengue devido à sua influência direta na ecologia do Aedes aegypti, principal vetor da doença. Em 2023 e no início de 2024, o Brasil registrou um número sem precedentes de casos de dengue — 3.000 por 100 mil habitantes, totalizando mais de 6 milhões de casos até julho de 2024 — coincidindo com temperaturas recordes. Este estudo examina a interseção entre a proliferação da dengue e as mudanças climáticas na Região Sul do Brasil, uma área historicamente menos afetada pela doença devido ao seu clima mais ameno. Por meio da análise de dados epidemiológicos e fatores climáticos, o artigo explora como o aumento das temperaturas e as alterações nos padrões de chuva criaram condições favoráveis à disseminação da dengue. Além disso, criticamos as atuais políticas de saúde pública no Brasil, particularmente as limitações de uma abordagem centrada no mosquito, e sugerimos estratégias mais abrangentes que abordem as vulnerabilidades socioambientais agravadas pelas mudanças climáticas. Este trabalho destaca a necessidade urgente de respostas integradas de saúde pública que considerem tanto os determinantes biológicos quanto os sociais da dengue diante das emergências climáticas em curso.
Copyright (c) 2025 Francisco Mendonça, Felipe José Soek, Antonio Carlos da Silva Oscar Junior, Thiago Kich Fogaça, Daniel Canavese, Mauricio Polidoro
Spatial Interpolation: Geoprocessing Applied to the Detection of Climate Change in Santa Catarina
The study addresses spatial interpolation as an essential tool for mapping climate change, especially in regions with a low density of meteorological stations. Given the growing climate threat and the need for accurate data for agricultural planning and water resource management, mapping the historical variability of precipitation and potential evapotranspiration in Santa Catarina becomes crucial. In this context, spatial interpolation enables a detailed analysis of the climate’s influence in the state. The study uses precipitation and evapotranspiration data from a historical series spanning 1960 to 2020, applying the IDW interpolator for spatialization. The validation of the interpolator is performed using statistical indices such as RMSE, EAM, and Willmott’s index. The results indicate significant seasonal variation, with higher precipitation in summer and lower in winter, while distinct patterns are observed between mountainous and coastal regions, influenced by altitude and atmospheric circulation. The validation confirms the high performance of the interpolator in estimating variables. Thus, spatial interpolation proves to be an efficient technique for accurately representing climate variations, contributing to water management and agricultural planning. The generated maps provide technical support to mitigate the impacts of climate change and optimize agricultural practices in Santa Catarina.
Copyright (c) 2025 Pablo Francisco Benitez Baratto, Jackson Adriano Albuquerque, Claudia Guimarães Camargo Campos
Precipitation time series model for the city of Chimoio-Mozambique
Since 1970, the world has been witnessing an increase in temperature and an intensification of the hydrological cycle, resulting in a greater amount of water vapour in the atmosphere and making water availability less predictable and more variable. The Identification of meteorological changes in records is very important for hydrological simulations using stochastic models, in focus on prediction and preparing the society for possible extreme or rare events impacts, Thus, this study aimed to analyse the temporal monthly rainfall variability in Chimoio city by adjusting a time series model for the period from 1989 to 2022. The methodology applied is the analyse of monthly variability of precipitation using the coefficient of variation and trend analysis, with the adjustment of the time series precipitation model based on the method proposed by Box and Jenkins (1976). The results indicated a relationship between the El Niño-Southern Oscillation (ENSO) phenomenon and precipitation variability, with higher variability in the months of November, December, January, and February. Annually, the year 2008 showed the greatest variability. The trend analysis revealed statistical significance for the month of August, becoming significant from 1994 onwards. The SARIMA (7,0,1)(0,1,1)12 model was selected to forecast future observations, with all predictions for the year 2022 falling within the 95% confidence interval established by the model, despite unforeseen events and uncertainties associated with climatic factors.
Copyright (c) 2025 Jone Chacuinda Sumbulero, Noé Osório Macário , Luiz Otávio de Oliveira Pala , Luiz Fernando Coutinho de Oliveira , Thelma Sáfadi , Paulo Henrique Sales Guimarães
Analysis of the mitigating effect of the microclimate of the understory forest of the Adolpho Ducke Forest Reserve in Central Amazonia
Vegetation cover plays a fundamental role in modulating the microclimate and regulating hydrological processes, particularly in sensitive ecosystems such as the Amazon rainforest. This research was conducted in the Adolpho Ducke Forest Reserve, in Manaus, Amazonas, between December 2020 and June 2021, with the aim of evaluating the interaction between vegetation structure and microclimate in the dynamics of surface soil moisture, comparing areas of understory and clearings. The study also aims to measure the capacity of the forest ecosystem to buffer climate variations and its relevance to hydrological processes in the region, which is increasingly vulnerable to climate change. Measurements of incident solar radiation, air temperature and relative humidity, soil moisture, and precipitation were taken. The results indicated a significant loss due to interception, estimated at 46.79% in the understory area. The vegetation cover blocked about 94.85% of solar radiation, resulting in a milder microclimate, with daily temperatures up to 4.0 °C lower and relative humidity 15.0% higher in the understory compared to the clearing. In addition, the understory soil remained moister on dry days, with stable vapor pressure deficit. These findings reinforce the importance of vegetation cover in modulating the local microclimate, which is essential for maintaining soil moisture and mitigating the effects of climate change in the Amazon rainforest. Monitoring these variables is critical for understanding the impacts of land use changes and global climate, providing input for conservation and sustainable management policies in the Amazon.
Copyright (c) 2025 Keully Melo de Souza , Luiz Antonio Candido, Polari Batista Corrêa, Maria Juliana de Melo Monte, Willian Miguel Pereira Ramos , Gleice Guerreiro Timoteo
Modeling the Temporal Trend of Extreme Temperature and Precipitation Events in the City of Quelimane, Zambézia Province
This study aims to analyse the temporal trends of extreme temperature and precipitation events in Quelimane City. Daily meteorological data from the past 38 years were obtained from the National Institute of Meteorology with the objective of identifying the trends in extreme events. After data verification and correction, fourteen internationally recommended climate indices were applied to evaluate and to predict the extreme events. The analysis indicated a gradual increase in average temperatures, with maximums around 30,6 °C and minimums around 20,5 °C, and a statistically significant warming trend over the time. A reduction in dry period was observed with an average decrease of 70 days since 1985, as well as increase in wet period from approximately 60 to 70 days. Rainfall intensity showed notable peak in 1992 and 2012. Forecasts, based on the ARIMA (Autoregressive Integrated Moving Average) models, indicate that over the next 10 years, maximum temperatures will remain stable (34 °C to 35 °C) while minimum temperatures will gradually rise (25 °C to 26 °C). For precipitation, a decrease in the total amount of extreme rainfall (R95PTOT) is expected alongside a possible increase in the number of days with heavy rainfall (R50mm) reaching up to seven days per year by 2027.
Copyright (c) 2025 Richard Boaventura Inosse Zinenda, Arlindo Meque , Martes Domingos Louvane Macajo
Análise das séries históricas de precipitação na Bacia Hidrográfica do Camaquã, RS, Brasil, a partir de dados observados e numéricos de alta resolução
O presente artigo aborda a análise das séries históricas de precipitação na Bacia Hidrográfica do Camaquã (BHC), localizada no Rio Grande do Sul, Brasil. O estudo destaca a relevância do monitoramento climático, especialmente para entender variações na precipitação, que impactam atividades econômicas locais, como a agricultura e a pecuária. O objetivo principal é identificar e preencher lacunas nos dados históricos de precipitação, utilizando métodos estatísticos, como a regressão linear múltipla, e verificar tendências de precipitação ao longo de 40 anos (1981-2020). A pesquisa também correlaciona dados históricos com a reanálise, visando avaliar a precisão desse modelo. Os resultados mostram uma distribuição média razoavelmente homogênea ao longo dos meses, com a primavera apresentando valores um poco maiores. A série histórica não apresentou tendências significativas. Observou-se que o ERA5 apresenta forte correlação com os dados observados, embora tenda a superestimar a precipitação principalmente nos meses mais quentes.
Copyright (c) 2025 Taís Pegoraro Scaglioni, Mateus Menezes Straceione , André Becker Nunes
The thermohygrometric Field, in the Copacabana-RJ neighborhood, in a seasonal spring situation
Copacabana is a symbol of the arrival of modernism in Brazil. The consequence was the convergence of populations, which soon led to verticalization. The neighborhood is the most vertical in the city. Due to this landscape transformation, this study seeks to analyze the thermohygrometric field during the spring season (November 2, 2024). To this end, mobile transects were used in the morning (8:00 a.m.) and night (9:00 p.m.). Among the results, spatialization was strongly influenced by the busiest traffic routes; the apparent path of the sun, which contributes to the concentration of lower temperatures on Figueiredo de Magalhães St., and higher temperatures in the inner part of the neighborhood, at the beginning of Siqueira Campos St.
Copyright (c) 2025 Edson Soares Fialho, Aline Szvarça Magalhães, Larissa Galvão Fontes dos Santos , Wesley de Souza Campos Correa, Laura de Souza Magalhães, Livia da Cunha Agrizzi
Application of Benford's law in monthly series of precipitation
Benford's Law describes a logarithmic distribution of leading digits in real-world data, with smaller digits occurring more frequently than larger ones. Accordingly, this study investigated the application of this law to monthly precipitation series recorded at nine automatic weather stations in the state of Espírito Santo, Brazil, from 2006 to 2023. The objective was to assess the conformity of the data with the theoretical distribution predicted by Benford's Law, both in the original data and after filling gaps in the series. Two gap-filling methods were used: the average of the same months from other years with data and linear interpolation. Adherence to Benford's Law was verified using the Chi-square test, comparing the observed distribution of the first and second digits with the expected theoretical pattern. The results indicated that the original precipitation series adheres to Benford's Law, suggesting the reliability of the records. Gap-filling with the average altered the digit distribution, particularly for the second digit, compromising this conformity. In contrast, linear interpolation preserved the numerical pattern and adherence to the law. It is concluded, therefore, that Benford's Law has the potential to assess the quality of precipitation series, and linear interpolation is recommended for treating missing data when it is necessary to preserve the initial natural distribution of the data.
Copyright (c) 2025 Iulo Pessotti Moro, Sidney Sara Zanetti, Roberto Avelino Cecílio
Analysis of precipitation indexes using BR-DWGD data in Terra Nova watershed, Pernambuco
This study investigated the temporal variability of precipitation indices in the Terra Nova River basin, located in the state of Pernambuco, using different climatic precipitation indices. The Precipitation Concentration Index (PCI), Precipitation Anomaly Index (RAI), Simple Daily Intensity Index (SDII), as well as absolute indices such as R0 mm, R0.1 mm and R50 mm, and the Mann-Kendall test were analyzed. The data used consist of historical series of daily precipitation from the Brazilian Daily Weather Gridded Data (BR-DWGD) product, covering the period from 1961 to 2022. The analysis revealed that the basin presented an average PCI of 21 and an average RAI of -0.14, suggesting a persistent drought pattern and irregularity in rainfall distribution. An annual average of 127 days without precipitation was observed, with only seven years recording daily rainfall above 50 mm. The average SDII was approximately 6 mm/day, a value considered one of the lowest in Brazil, according to previous studies. The Mann-Kendall test was applied with good performance to identify trends, although no statistically significant trends were detected in the indices and precipitation at different scales. This study demonstrated the ability of using BR-DWGD data to describe in detail the methodology used to assess the rainfall regime in river basins, offering a clear view of hydrological patterns quickly, being a useful tool for water resource management.
Copyright (c) 2025 Juarez Antônio da Silva Júnior
Principal components analysis and contributions of variables and weather stations in determining reference evapotranspiration in the Stade of Rio Grande do Sul
Reference evapotranspiration (ETo) is fundamental in hydrology and meteorology, and is widely used in climate change prediction and land use. This study used principal component analysis (PCA) to determine the contributions of meteorological variables and stations in estimating ETo, employing daily data from thirteen meteorological stations in the State of Rio Grande do Sul from 1990 to 2022, categorized by seasonal periods. The first three principal components explained 85.6% of the total ETo variability in spring, 87.9% in summer, 81.5% in autumn and 80.4% in winter. Tmax, RHmin and Rs were the most significant meteorological variables in spring, summer and autumn, while u2 and Rs stood out in winter. The stations with the largest contributions were: Uruguaiana, Bom Jesus, Torres, São Borja and SLG in spring and summer; Bom Jesus, Encruzilhada - Canguçu, São Borja and SLG (autumn); and Camaquã, Passo Fundo, Porto Alegre and Torres in winter. These results provide accurate information on the meteorological variables and seasons that influence ETo, highlighting climate variability on seasonal scales and contributing to an adequate representation of regional water demand.
Copyright (c) 2025 Giane Lavarda Melo, Mirta Teresinha Petry, Juliano Dalcin Martins, Bruna de Villa
Temporal analysis of climatological variables: an approach with sliding windows
This research aims to analyze the fluctuations of the variables air temperature, relative humidity and solar radiation of the city of Feira de Santana, Bahia, Brazil with the sliding windows procedure in the period from 2009 to 2019. The analysis was performed in two stages: 1 - exploratory data analysis (mean, standard deviation, coefficient of variation, asymmetry, kurtosis, minimum and maximum); 2 - sliding windows (descriptive statistics, autocorrelation, bivariate and multivariate cross-correlation). The autocorrelation was measured with the exponent of the method Detrended Fluctuation Analysis-DFA, the bivariate and multiple cross-correlation with the coefficients ρDCCA and DMC, respectively. The DFA analysis indicated long-range persistent behavior (α > 0.5) in the time series of the three climatological variables studied. The ρDCCA modeling revealed a predominantly positive correlation between air temperature and solar radiation in all time scales and analyzed windows. There was a negative correlation between solar radiation and relative humidity. The air temperature and relative humidity showed negative cross-correlation, from moderate to very strong, in almost all scales. The multiple cross correlation between variables was qualitatively strong to very strong, especially on larger scales. The results reinforce the effectiveness of the applied methods for climatological data modeling and contribute to the literature by dynamically characterizing autocorrelations and cross-correlations (bivariate and multivariate) of the studied variables.
Elvira Catiana de Oliveira Santos Ferreira
Copyright (c) 2025 Taíze da Silva Sousa, Elvira Catiana de Oliveira Santos Ferreira, Everaldo Freitas Guedes, Aloisio Machado da Silva Filho
Human thermal comfort on cycling paths in Fortaleza, Ceará
Intensified urbanization and the replacement of vegetation with impervious surfaces have altered urban climates, raising temperatures and increasing thermal discomfort, especially in tropical cities. Bikeways, as a sustainable mobility alternative, are affected by these changes, particularly when located in dense urban areas with limited shade and low-albedo materials. This study analyzed human thermal comfort across different types of cycling infrastructure in Fortaleza, Brazil, focusing on the relationship between thermal sensation, vegetation cover, and urban materiality. A mobile transect survey was conducted along an 8 km route, recording air temperature and relative humidity. The Heat Index (HI) was applied to estimate thermal discomfort, and the results were correlated with NDVI and built volume data surrounding the bikeways. The findings indicate that segments with dense vegetation and permeable pavements provided more favorable thermal conditions, while asphalted sections with high building density and minimal tree cover recorded the highest discomfort levels, even at night. These results emphasize the importance of integrating thermal comfort criteria into cycling infrastructure planning, highlighting that the promotion of active mobility depends on supportive environmental conditions. Therefore, bikeways should be designed not only as transport corridors but also as climate-sensitive urban spaces that enhance quality of life in tropical cities.
Copyright (c) 2025 João Neftali Freire Amaral, Antonio Ferreira Lima Júnior, Francisca Mairla Gomes Brasileiro, Lidia Gomes de Castro
Governance and public policies for climate change in Rio Grande do Norte, Brazil
Extreme weather events on Earth have spurred a political and governmental agenda to address it. This study aims to examine the institutional context of climate change in the state of Rio Grande do Norte from 2000 to 2023. For this, a documentary exploratory-descriptive research was carried out that delimited the diagnosis into four main axes: I - planning; II - laws, regulations, and resolutions; III - actions and projects; and IV - events, forums, councils, and state departments. Data collection and analyses of specific documents from each axis were carried out following guiding questions in connection with the objective of this study. This research found that the recent normative and programmatic framework that governs the decision-making processes in Rio Grande do Norte regarding the climate has evolved timidly, having gained more repercussions within the scope of the State Multi-Year Plans and in state legislation, although it is essential to broaden the theme considering the climatic conditions and human alterations that make the state territory vulnerable to climate change.
Copyright (c) 2025 Diógenys da Silva Henriques, Anny Catarina Nobre de Souza, Wanessa Dunga de Assis, Agassiel de Medeiros Alves, Leonlene de Sousa Aguiar
Analysis of pluviometric characteristics of the Hydrographic Basin of the Paraíba do Sul River
Knowing the pluviometric characteristics of a region is important for various socioeconomic and environmental sectors. Therefore, the objective of this study was to identify pluviometrically homogeneous regions and characterize the spatiotemporal variation of precipitation in the Paraíba do Sul River Basin (BHRPS). Daily data from 89 pluviometric stations of the hydrometeorological network managed by the National Water and Basic Sanitation Agency (ANA) were used for the period from 1963 to 2022. To determine the pluviometrically homogeneous regions, the means and the 15%, 35%, 65%, and 85% quantiles per season were used as variables. To estimate trends and their magnitudes, the Mann-Kendall test and Sen's slope estimator were employed. Two pluviometrically homogeneous regions were identified, with region 2 (with 12 pluviometric stations located in the central-western and southeastern portions of the BHRPS) showing higher precipitation values than region 1 (with 77 pluviometric stations distributed throughout the BHRPS). In region 1, the lowest precipitation values were identified in the northeastern part of the BHRPS. Statistically significant negative trends at 5% were identified for the analyzed quantiles in two pluviometric stations (regions 1 and 2), while a statistically significant positive trend was observed in one pluviometric station (region 1). The highest precipitation values in the BHRPS occurred in summer, with average monthly rainfall ranging from a minimum of 131.53 mm (region 1) to a maximum of 393.57 mm (region 2), while the lowest values were recorded in winter, with a minimum of 15.75 mm/month (region 1) and a maximum of 65.10 mm/month (region 2). These results contribute to a better understanding of the region's climate patterns and provide support for water resource planning and management, aiding strategic decision-making for environmental sustainability.
Copyright (c) 2025 Bárbara Velasco Holender, Gildo Rafael de Almeida Santana , Eliane Barbosa Santos
Climate classifications: methods, characteristics and objectives in climate study
Climate classifications are essential for understanding weather patterns at different scales, with applications in agriculture, urban planning, and environmental studies. This study aims to relate different climate classifications, analyzing their purposes, application contexts and impacts on research and classification processes. To this end, a systematic review based on the PRISMA protocol was carried out, with the analysis of 31 articles published between 2000 and 2023, selected from the Web of Science and Scopus databases. The results showed a constant search for the improvement of climate classifications, with emphasis on the Köppen, Köppen-Geiger and Köppen-Trewartha systems, widely used in the elaboration of climate maps, identification of climate change and evaluation of environmental impacts. In addition, the importance of these classifications for scientific advancement was evidenced, with applications in areas such as health, hydrology, vegetation and energy. The systematic review revealed a wide diversity of applications of climate classifications, but also highlighted that most studies focus on improving existing classifications and developing new mappings. This indicates that, despite the recognized relevance of these tools, there are still gaps and challenges to be overcome in order to create more accurate and comprehensive methods capable of meeting current and future climate-related demands.
Copyright (c) 2025 Maria do Socorro Silva Salvador, Tony Vinicius Moreira Sampaio, Pedro Augusto Breda Fontão
Microclimate and vegetation: an assessment in the city of Paragominas-PA
Public spaces, such as squares, forests, avenues, etc., relatively attenuate the amount of solar radiation reaching the Earth's surface and alter thermal comfort. The main goal of this research is to identify the need for adequate afforestation, on public roads, to maintain the microclimate and thermal comfort in three areas within the urban perimeter of the city of Paragominas-PA: 1) Environmental Park; 2) Célio Miranda Square; and 3) Teresina Avenue. The research method was investigative regarding thermal comfort, and the micrometeorological data was quantitatively and qualitatively analyzed. This method was applied in four phases: 1) location of four collection points (P1, P2, P3, P4); 2) taxonomic identification of local vegetation; 3) data measurement at 8:00 a.m. and 12:00 p.m.; and 4) analysis of the data obtained. At the four points, the following were recorded: air temperature (26.0 ≤ 32.6 °C); Radiant heat capacity (CTR) (457 ≤ W/m² ≤ 598); Relative humidity (65.56 ≤ % ≤ 77.79); Thermal discomfort index (25.47 ≤ IDT ≤ 27.47); and wind speed (0.28 ≤ m/s ≤ 1.29). For the Environmental Park, these measurements proved to be adequate for maintaining thermal comfort. In Célio Miranda Square and Teresina Avenue, the averages indicated a loss in comfort quality. Therefore, it was proven that the type of tree cover on A2 maintains thermal comfort; on A1 and A3, this statement is not true. Given this result, the need to restore and maintain these spaces to regulate the local microclimate is noted.
Copyright (c) 2025 Fagner Lopes Guedes, Laís de Gusmão Coutinho , Seidel Ferreira dos Santos , Eliane De Castro Coutinho
Hydrological Projections Of the Madeira River (2025–2030) Under Cmip6 Climate Scenarios Ssp1-2.6 And Ssp5-8.5
With the increase in greenhouse gas emissions and the consequent changes in weather patterns, understanding and predicting climate change is of utmost importance for decision-making and formulation of effective mitigation and adaptation policies. It is in the context of this regional vulnerability to climate change and the uncertainties arising from these changes that this study is situated. Aiming not only to project water levels but also to translate these projections into concrete operational impacts for the waterway sector. Artificial neural networks were developed using the multilayer perceptron architecture. Two test scenarios were performed, scenario SSP1-2.6 presents reduced greenhouse gas (GHG) emissions, while scenario SSP5-8.5 presents more intense emissions. The inputs of the ANNs consist of precipitation, temperature, humidity and water level data from the stretch from Porto Velho to Humaitá. The network output is composed of the predicted water level of the Humaitá station for the period from 2025 to 2030. Scenario 1 (SSP1-2.6) presented a variation in water level values ​​of approximately 800 cm to 1500 cm for the projected period from 2025 to 2030. Meanwhile, scenario 2 (SSP5-8.5) showed water level values ​​ranging from 800 cm to 2400 cm. In scenario SSP1-2.6, the variation in the water level of the Madeira River was more moderate, while scenario SSP5-8.5 presented higher water levels. The results reinforce the need for planning and adaptation of the waterway sector in the face of climate change.
Copyright (c) 2025 Carolina Costa Ramos, Ana Cibelle Tavares Leal
Evaluation of moisture in sugarcane straw bales piles in the field using geoestatistical techniques
Sugarcane is planted in 23 Brazilian states totaling more than 10.2 million hectares, and for each hectare there are around 10 tons of straw (db), biomass resulting from mechanized harvesting. In Brazil, the straw is of relevance to the sector by the volume produced and can be used for the production of steam, electricity, second-generation ethanol, and paper, and the bale is the most used form in field harvesting. Due to the sugarcane harvesting, it is necessary to store the bales produced in large piles for up to one year. The best way to store bales of straw is still unknown, which leads to biomass losses, higher costs, and reduced profits. In order to provide more efficient techniques for the storage of straw, we evaluated the distribution of moisture inside the piles stored in the field, without coverage, in two baling densities, three accumulated amounts of precipitation, and the picking or not of the straw before the baling. Over all, nine piles were assembled, and 294 moisture points per pile were sampled. The analysis and data processing consisted in verifying the existence of spatial dependence, and existing, the data interpolation was carried out by the ordinary kriging method by prediction, to estimate values at unmeasured locations and to create the moisture distribution maps in the stacks. In all the evaluated treatments the existence of spatial dependence was observed, being possible the use of geostatistical methods for analysis. The spherical model was the most appropriate to describe the behavior of moisture inside the cells. The chopping of straw affected the distribution of moisture, as well as the density and amount of precipitation accumulated. For short periods of storage, bales of chopped straw remained drier, while for longer periods, bales of chopped straw remained drier. High-density bales were more efficient in maintaining the driest biomass.
Copyright (c) 2025 Marcelo Scantamburlo Denadai, Saulo Philipe Sebastião Guerra, Emanuel Rangel Spadim, Humberto de Jesus Eufrade Junior
Analysis of the Atmospheric Environment associated with the Extratropical Cyclone that formed in Rio Grande do Sul – July 2023
This study aims to describe and identify the synoptic-scale atmospheric environment associated with the extratropical cyclone that hit the state of Rio Grande do Sul on July 12 and 13, 2023. The passage of the cyclone affected 82 municipalities, affecting 5,889,672 people, of which 55,912 were directly impacted, with 620 displaced, 7,504 houses unroofed, and 58 houses destroyed. To analyze the event, images from the infrared channel of the GOES16 satellite and reanalysis data from ERA5 were used to obtain the meteorological fields. The synoptic analysis demonstrated the formation of the already intense system still over the continent, and that dynamic and thermal factors contributed to its occurrence. The dynamic forcing was the advection of cyclonic vorticity due to the presence of a mid-level trough (500hPa) upstream, and the thermal related to the transport of heat and moisture from the north, which contributed to the intensification of the system. The origin of the low pressure system began over the interior of the continent, the so-called Northwestern Argentinean Low (NAL), intensified by a strong convergence of the moisture flux at low levels, with the presence of the low-level jet and diffluent flow at high levels.
Copyright (c) 2025 Luciana Cardoso Neta , Luiza Denardi Cesar, Mônica Navari Kurz, André Becker Nunes
Spatiotemporal Dynamics of Fire Hotspots in the Taiamã Ecological Station and Surroundings
This study analyzes the spatiotemporal dynamics of fire hotspots in the Taiamã Ecological Station, a protected area located in the Pantanal of Mato Grosso, and its surrounding zone, between 2000 and 2024. Remote sensing data from MODIS sensors were used, complemented by information from the National Institute for Space Research (INPE). The results reveal the recurrent occurrence of fire hotspots in all evaluated years, with higher concentration between August and October, coinciding with the regional dry season. Notably, atypical events were recorded in January and February 2024, when the hydrological seasonality of the Paraguay River and rainfall regime would be expected to ensure humid conditions. This anomaly suggests an association with rainfall deficits and the exposure of highly combustible organic material typical of the region. The persistence and temporal expansion of fire events indicate increasing vulnerability of the protected area in the face of changes in the Pantanal’s hydrological regime. Strengthening systematic monitoring strategies, adaptive management of fire and water, ecological restoration, and socio-environmental education programs is fundamental to mitigate risks and safeguard the ecological integrity of Taiamã Ecological Station, a unique ecosystem of high conservation value.
Copyright (c) 2025 Ernandes Sobreira Oliveira Júnior , Derick Vitor de Souza Campos , Maísa Consuelo dos Santos, Janaina Vetoreti Goloni, Bruna Caroline Paspardelli Cortelete, Danúbia da Silva Leão, Érico Fernando de Oliveira Martins, Solange Kimie Ikeda Castrillon
Variability of Rainfall Erosive Potential in Mountainous Areas: A Trend and Change Point Analysis of Rainfall Erosivity in Petrópolis, Rio de Janeiro, from 1940 to 2022
The erosive potential of rainfall is a critical variable for understanding environmental impacts, especially in areas with complex terrain. This study analyzed trends and points of change in rainfall erosivity in the municipality of Petrópolis, located in the mountainous region of the state of Rio de Janeiro. Erosivity was calculated using the EI30 index, derived from the Modified Fournier Index (MFI), and the nonparametric Mann-Kendall and Pettitt tests were applied to identify trends and points of change in the historical series. The results indicated positive trends of increased erosive potential in three of the five stations, especially in the months of May, June, September, and November. The greatest changes occurred in the leeward areas, contrary to the expectation of greater impact in the windward areas.
Copyright (c) 2025 Camila de Moraes Gomes Tavares, Núbia Beray Armond, Cássia de Castro Martins Ferreira, Antonio José Teixeira Guerra
Monthly and seasonal behavior of average temperature and relative air humidity in the ecoregions of the Caatinga Biome
This study analyzed the monthly and seasonal behavior of average temperature (TMéd) and relative humidity (RH) in the eight ecoregions of the Caatinga biome between 1980 and 2022, using data from 56 meteorological stations. The objective was to identify climatic patterns, trends, and anomalies that influence the vegetation and local ecosystems. The methodology included multiple imputation (BootEM method) to fill gaps in the data and spatial interpolation by ordinary kriging to map the variables. The results revealed significant variations in TMéd (22°C to 31°C) and RH (39% to 91%) among the ecoregions. The Northern Sertaneja Depression (EDSS) and the Ibiapaba-Araripe Complex (ECIA) presented the highest TMéd, while the Borborema Plateau (EPB) recorded the highest RH. Seasonal patterns showed higher temperatures between October and March and reduced RH during the dry months (September–October). The discussions highlighted the influence of topography, solar radiation, and atmospheric systems on climate variability. Regions with lower relative humidity (RED) (EDSM) face a greater risk of desertification, while areas with high average temperatures (AIT) (ECCM) are more vulnerable to droughts. It was concluded that, through the evaluation of 42 years of data, it was possible to observe variable climate trends in the ecoregions. The EDSS and ECIA, therefore, show trends of a more noticeable increase in average temperature, mainly in years of strong El Niño occurrence, such as 1998 and 2016. On the other hand, ecoregions such as the ECCD demonstrated greater thermal stability, indicating that the trends of increasing temperature are not homogeneous throughout the Caatinga.
Copyright (c) 2025 Maxsuel Bezerra do Nascimento, Gabrielo Victor Silva do Nascimento, Thales Nunes Martins de Sá, Itauan Dayvison Gomes de Medeiros, Gizelly Cardoso Lima, Claudio Moises Santos e Silva
The The 20th anniversary of the Brazilian Journal of Climatology and its leading role in the knowledge about climate and its relations with society and the territory
In celebration of Brazilian Journal of Climatology 20th anniversary, this article aims to analyse the scientific production published between 2005 and 2024. The articles were classified using criteria such as the central theme addressed, the climate element used, the theoretical and applied application, the time scales and territorial scopes, as well as the sector of climate science in which they are included. The impact of the articles was also demonstrated through the number of citations and downloads made, both of the articles and their authors. The institutions of origin and their geographic distribution were quantified. Thus, an overview of the journal's profile is presented and ends with an assessment of its contribution to scientific knowledge in climate science.
Copyright (c) 2025 João Lima Sant'Anna Neto
RBClima at LABOCLIMA-UFPR: challenges of computing and spectrum expansion
RBClima – Brazilian Journal of Climatology, was created in 2005 by ABClima – Brazilian Association of Climatology; since the beginning, the quality of publications has been guaranteed by blind evaluation and in accordance with Qualis/CAPES parameters. Between 2011 and 2016, the journal underwent changes in its structure and the journal's editing was under the responsibility of LABOCLIMA/UFPR, during which 12 issues were published. During this period, it switched to an electronic version, in addition to the printed version, and was managed through the SEER/UFPR System; the number of members of the scientific committee and ad hoc evaluators was increased, and it also began to accept publications in english, french, and spanish. In celebrating its 20th anniversary, RBClima has consolidated itself as one of the most relevant journals in the publication of climate scientific papers, with emphasis on the topics of climate change, extreme weather events, climate modeling, etc.
Copyright (c) 2025 Francisco de Assis Mendonça, Wilson Flávio Feltrim Roseghini, Francisco Jablinski Castelhano
From analog to digital: the paths of the Brazilian Journal of Climatology (RBClima) and its role in strengthening Geographical Climatology
This text presents a historical and personal account of the Brazilian Journal of Climatology (RBCLIMA), indicating its different stages, difficulties, and paths followed over the last two decades. It demonstrates the different editorial processes throughout this period and future directions for this journal.
Copyright (c) 2025 Emerson Galvani, Francisco Jablinski Castelhano