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Subseasonal-to-seasonal (S2S) precipitation prediction in boreal spring and summer months, which contains a significant number of high-signal events, is scientifically challenging and prediction skill has remained poor for years. Tibetan Plateau (TP) spring observed surface ­temperatures show a lag correlation with summer precipitation in several remote regions, but current global land–atmosphere coupled models are unable to represent this behavior due to significant errors in producing observed TP surface temperatures. To address these issues, the Global Energy and Water Exchanges (GEWEX) program launched the “Impact of Initialized Land Temperature and Snowpack on Subseasonal-to-Seasonal Prediction” (LS4P) initiative as a community effort to test the impact of land temperature in high-mountain regions on S2S prediction by climate models: more than 40 institutions worldwide are participating in this project. After using an innovative new land state initialization approach based on observed surface 2-m temperature over the TP in the LS4P experiment, results from a multimodel ensemble provide evidence for a causal relationship in the observed association between the Plateau spring land temperature and summer precipitation over several regions across the world through teleconnections. The influence is underscored by an out-of-phase oscillation between the TP and Rocky Mountain surface temperatures. This study reveals for the first time that high-mountain land temperature could be a substantial source of S2S precipitation predictability, and its effect is probably as large as ocean surface temperature over global “hotspot” regions identified here; the ensemble means in some “hotspots” produce more than 40% of the observed anomalies. This LS4P approach should stimulate more follow-on explorations.

An experiment reported in Mesinger and Veljovic (JMSJ 2020) showed anadvantage of the Eta over its driver ECMWF ensemble members in placing 250 hPa jetstream winds during a period of an upper tropospheric trough crossing the Rockies. Abyproduct of that experiment was that of the Eta ensemble switched to use sigma,Eta/sigma, also achieving 250 hPa wind speed scores better than their driver members,although to a lesser extent. Nevertheless, it follows that the Eta must include feature orfeatures additional to the eta coordinate responsible for this advantage over theECMWF.An experiment we have done strongly suggests that the van Leer type verticaladvection of the Eta, implemented in 2007, is a significant contributor to this advantage.In this experiment, having replaced a centered finite-difference Lorenz-Arakawa schemethis finite-volume scheme enabled a successful simulation of an intense downslopewindstorm in the lee of the Andes.While apparently a widespread opinion is that it is a disadvantage of terrainintersecting coordinates that “vertical resolution in the boundary layer becomes reducedat mountain tops as model grids are typically vertically stretched at higher altitudes,” avery comprehensive 2006 NCEP parallel test gave just the opposite result. Withseemingly equal ABL schemes, the Eta showed a higher surface layer accuracy overhigh topography than the NMM, using a hybrid terrain-following system (Mesinger, BLM2022).Hundreds of thousands of the Eta forecasts and experiments performeddemonstrate that the relaxation lateral boundary conditions almost universally used inregional climate modeling (RCM)–in addition to conflicting with the properties of thebasic equations used–are unnecessary. Similarly, frequently applied in RCMs so-calledlarge scale or spectral nudging, being based on an ill-founded belief, should only bedetrimental if possible numerical issues of the limited area model used are addressed.Note that this is confirmed by the results we refer to above.

The collaboration between the Coordinated Regional Climate Downscaling Experiment (CORDEX) and the Earth System Grid Federation (ESGF) provides open access to an unprecedented ensemble of regional climate model (RCM) simulations, across the 14 CORDEX continental-scale domains, with global coverage. These simulations have been used as a new line of evidence to assess regional climate projections in the latest contribution of the Working Group I (WGI) to the IPCC Sixth Assessment Report (AR6), particularly in the regional chapters and the Atlas. Here, we present the work done in the framework of the Copernicus Climate Change Service (C3S) to assemble a consistent worldwide CORDEX grand ensemble, aligned with the deadlines and activities of IPCC AR6. This work addressed the uneven and heterogeneous availability of CORDEX ESGF data by supporting publication in CORDEX domains with few archived simulations and performing quality control. It also addressed the lack of comprehensive documentation by compiling information from all contributing regional models, allowing for an informed use of data. In addition to presenting the worldwide CORDEX dataset, we assess here its consistency for precipitation and temperature by comparing climate change signals in regions with overlapping CORDEX domains, obtaining overall coincident regional climate change signals. The C3S CORDEX dataset has been used for the assessment of regional climate change in the IPCC AR6 (and for the interactive Atlas) and is available through the Copernicus Climate Data Store (CDS)., Bulletin of the American Meteorological Society, 103 (12), ISSN:0003-0007, ISSN:1520-0477

The present study gives evidence of the occurrence of foehn-like wind on the eastern slopes of the mountains at Southeastern Brazil. A particular case was detected based on observational evidence on 4 July 2015 near the city of Cruzeiro, state of Sao Paulo, on the Serra da Mantiqueira mountains. Results obtained from numerical simulations are consistent with the foehn wind occurrence deducted from the analysis of regional patterns and time series of selected meteorological parameters. Resumo O presente trabalho evidencia a ocorrência de vento tipo foehn nas encostas orientais das serras do Sudeste do Brasil. Um caso particular foi detectado a partir de evidências observacionais em 4 de Julho de 2015 perto da cidade de Cruzeiro, Estado de São Paulo, na Serra da Mantiqueira. Os resultados obtidos por simulações numéricas são consistentes com a ocorrência de vento foehn, como pode ser visto a partir da análise de padrões regionais e séries temporais de certos parâmetros meteorológicos.

Resumo Nesse estudo avaliou-se os impactos do aumento dos GEE's (cenário RCP 8.5) e dos desflorestamentos no ciclo da água na bacia do rio Madeira, utilizando o Modelo Regional Eta e o Modelo Hidrológico de Grandes Bacias (MGB), forçado com o Brazilian Earth System Model Ocean-Atmosphere versão 2.5 (BESM-OA 2.5). No cenário RCP 8.5, o modelo apresentou sensibilidade sobre toda a bacia do Madeira, com aumento da ordem de 4.0 °C na temperatura. O aumento foi intensificado com os cenários de desflorestamentos de 2050 (4.8 °C) e 2100 (6.2 °C). Nos cenários de desflorestamento predominou-se o Mecanismo de Retroalimentação Negativo, pois embora haja reduções na precipitação e evapotranspiração, a convergência de umidade aumentou em todos os cenários. Observou-se aumento das descargas na maioria das estações para todos os cenários futuros RCP 8.5 e desflorestamento. O aumento da precipitação na estação seca explicou em parte o aumento das vazões e na área de inundação sobre a bacia do Madeira. O aumento na precipitação à montante da bacia e a mudança nos parâmetros do solo, associada às alterações no uso da terra, contribuíram para o aumento da vazão e área de inundação sobre a bacia do Madeira. As alterações nas descargas e na área de inundação podem ter efeitos negativos, com prejuízos e danos ao meio ambiente, nos recursos hídricos, nos principais setores da economia, afetando de forma direta as comunidades que vivem às margens dos rios, principalmente as populações vulneráveis da bacia do Madeira. Abstract In this study, we evaluated the impacts of increased GHGs (RCP 8.5 scenario) and future deforestations on the water cycle in the Madeira River basin by using the Eta Regional Model and MGB-IPH Large-scale Hydrological Model, forced by Brazilian Model of the Terrestrial System (BESM-AO 2.5). In the RCP 8.5 scenario, the model demonstrated sensitivity over the entire Madeira basin, with a temperature increase of 4.0 °C. The increase was intensified with the deforestation scenarios for 2050 (4.8 °C) and 2100 (6.2 °C). In the deforestation scenarios, the Negative Feedback Mechanism (NFM) was predominant because, although there were reductions in precipitation and evapotranspiration, the convergence of humidity presented an increase in all the scenarios. Regarding the hydrological processes, an increase in the discharges in most stations for all future scenarios for RCP8.5 and deforestation was observed. The increase in precipitation in the dry season explains in part the increase in the discharges and in the flood area in the Madeira basin. The increased upstream precipitation and the changes in soil parameters associated with the changes in land use contributed to the increase in the flood area over the Madeira basin. These changes can have negative effects on the environment, on water resources and on the main sectors of the economy, which directly affect the communities that inhabit the river banks, especially the vulnerable populations of the Madeira basin.

This study investigates the spatial structure and the seasonal occurrence of foehn wind to the east of the Andes using a flow blocking analysis in a 20-year climate simulation. The latter was performed by the Eta-CPTEC regional model at 50-km horizontal resolution. This version of the model includes a cut-cell scheme to represent topography and a finite-volume vertical advection scheme for dynamic variables. The results indicate that foehn wind more frequently blows during winter and spring on the eastern slopes of the Andes, except to the south of 37° S where it blows at all seasons. Higher mountains of the Central Andes (27° S–35° S) and the High Plateau (15° S–27° S) result in blocked foehn events, with a weak adjustment to the geostrophic balance. On the Central Andes, rain and snow on mountain tops may also contribute to generate foehn wind on the eastern slopes. The results show that a low pressure develops to the east of the Central Andes, and also to the east of the High Plateau when foehn blows. Lower mountains in Patagonia (to the south of 37° S) result in more frequent non-blocked foehn event, with better adjustment to the geostrophic balance., Facultad de Ciencias Astronómicas y Geofísicas

We used climate models to assess the effects of 2 distinct anthropogenic forcings on the water budget in the Amazon basin: (1) increasing global greenhouse gases under the RCP8.5 scenario, and (2) land cover change caused by deforestation. The Eta regional climate model, driven by the Brazilian Earth System Model version 2.5 (BESM 2.5), was used to simulate the climate response under the RCP8.5 scenario and due to deforestation throughout the 21st century. Changes in energy and water budgets led to an increase in temperature that reached 5°C throughout the basin. In the RCP8.5 scenario, moisture convergence, precipitation and evapotranspiration all decreased. In this scenario, the positive feedback mechanism was predominant, as the reductions in evapotranspiration and moisture convergence acted in the same direction to reduce precipitation. In the future deforestation scenarios, reductions in precipitation were even stronger. In this case, the negative feedback mechanism predominated, in which the relative reduction in evapotranspiration was greater than the reduction in precipitation, leading to an increase in moisture convergence over the region. Changes in temperature and the water cycle were intensified in the future deforestation scenarios. These results show that the 2 anthropogenic factors can change the water budget and cause an imbalance in the climate-biome system in the Amazon basin, highlighting the need for public conservation policies to halt the increase in environmental degradation in the Amazon basin and to reduce greenhouse gases emissions due the burning of fossil fuels.

Made available in DSpace on 2022-04-28T19:28:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Agricultural activity is largely influenced by climatic conditions. Rainfall is essential for crop production, and precipitation events also interfere with soil preparation, planting, application of pesticides and harvesting. Weather forecast models are tools to facilitate decision making for agricultural activities, hence high accuracy is desired. Farmers often criticize the accuracy of weather forecasts, which sometimes fail to predict precipitation events, leading to yield loss and environmental harm. In this study, precipitation forecasts of the Eta Model were evaluated for 28 of Brazil’s most productive sugarcane areas, considering a grid of 15 × 15 km. Using a combination of different indicators of forecast success, observed and forecasted daily precipitation data were compared for consecutive days of all 10-day periods in a course of 6 years (2005–2010). Skill scores and performance diagrams based on the indicators were used to evaluate the goodness and robustness of the model forecasts. The Eta Model forecasts showed overall accuracies ranging between 55 and 71% for the Atlantic forest biomes (located North-West and South-East of São Paulo) and the Cerrado biomes (located in the Goiás State and in the Center-North São Paulo State), respectively. The forecasts were most reliable for up to 4 days, showing an accuracy of 60%. Forecasts for periods of more than 4 days had an average accuracy of 40–50%. The probability of detecting rainfall correctly was the strongest characteristic of Eta Model, with more than 70% hits. Department of Mathematical Sciences Faculty of Agricultural and Veterinarian Sciences University of São Paulo State, Prof. Paulo Donato Castellane Flemish Institute for Technological Research (VITO), Boeretang 200 Department of Earth and Environmental Sciences KU Leuven, Celestijnenlaan 200E Center for Weather Forecasts and Climate Studies National Institute for Space Research Av. dos Astronautas

Sao Tome and Principe is a small insular African country extremely vulnerable to rising sea levels and impacts such as inundation, shore line change, and salt water intrusion into underground aquifers. Projections of climate change have considered coarse model resolutions. The objective of this work is to dynamically downscale the global model projections to 4-km resolution and to assess the climate change in the Sao Tome and Principe islands. The global climate projections are provided by the Canadian Earth System Model under two Representative Concentration Pathways greenhouse gas scenarios, RCP4.5 and RCP8.5. The downscaling is produced by the Eta regional climate model. The baseline period is taken between 1971 and 2000, and the future climate period is taken between 2041 and 2070. The 2-m temperature simulations show good agreement with station data. The model simulates temperature more accurately than precipitation. The precipitation simulations systematically show underestimation and delay of the rainy and the dry seasons by about 1 month, a feature inherited from the global climate model. In the middle of the 21st century, projections show the strongest warming in the elevated parts of the Sao Tome Island, especially in February under RCP8.5. Warmer nights and warmer days become more frequent in the islands when compared with those in the present. While under RCP4.5, precipitation increases in the islands; under RCP8.5, it decreases everywhere in both islands. Heavy precipitation rates should increase, especially in the south-southwestern parts of the Sao Tome islands. Detailed spatial variability of the temperature and precipitation changes in the islands can only be revealed at very high spatial model resolution. Implications for the potential energy production from two major river basins are assessed in this work.

Este trabalho analisa as climatologias da temperatura do ar e da precipitacao da Bacia do rio Paraiba do Sul (BRPS), localizada na Regiao Sudeste do Brasil. A precipitacao anual varia entre 1000 mm no norte do estado do Rio de Janeiro e 2000 mm sobre a Serra da Mantiqueira. Aproximadamente 80% da precipitacao da bacia concentra-se nos meses de outubro a marco, sugerindo um regime monconico na regiao. A media anual da temperatura media diaria varia entre 16°C no extremo sudoeste e 22°C no extremo norte da BRPS. Essa grande variacao se deve a localizacao da BRPS na regiao de transicao entre latitudes medias e tropicais. O efeito da passagem de frentes frias sobre a temperatura e o efeito da atuacao da Zona de Convergencia do Atlântico Sul sobre a precipitacao podem ser observados na distribuicao espacial e temporal das variaveis estudadas.

Paleoclimate simulations are generally performed using coarse global climate models. However, validation of these simulations using a local dataset may be penalized by the coarse grid of the global models. Using a regional climate model, which benefits from the use of higher resolution in a limited area and specific period of time, may help improve the validation of the simulations and help to understand the climate of the past. The objective of this study is to evaluate the Mid-Holocene (MH) simulations for Brazil at 20 km spatial resolution using the regional Eta Model. The simulations are produced by nesting the Eta Model to the National Institute for Space Research (INPE) Global Spectral Atmospheric Model at T062 resolution and 28 vertical levels. Both global and regional models used the same orbital parameters to produce the Milankovic Cycles based on the Berger parameterization. The models adopted the typical carbon dioxide values for the present time and the MH. Downscaling simulations were performed with the Eta Model, resulting in simulations of 2 periods of time, the Eta 0k (present) and the Eta 6k (MH), each 10 years long. The evaluation compares these simulations against proxy data and other paleoclimate model simulations for the region. The difference between the two simulations, 6k and 0k, provides the changes between the two climatic periods. The Eta simulations indicate that the climate during MH was more humid over Northeast Brazil; this agrees partially with paleoclimate data in eastern Northeast Brazil. The Amazon region simulations were mostly drier during MH, in agreement with the paleoclimate data. A weaker convergence of winds in the MH, with winds blowing from the Amazon toward Southeast Brazil, affected the formation and the positioning of the South Atlantic Convergence Zone. Consequently, the associated moisture transport toward the Southeast was smaller; this reduced precipitation in the Brazilian southeastern, central-west, and southern regions, which agrees with the proxy data. The Eta Model simulated a cooler climate for the MH over the Northeast, Central, Southeast, and South Brazil. However, this simulated temperature showed less agreement against proxy data. The Amazon region was slightly warmer, and other transition regions showed no climate change. Overall, the results show that this modified version of the Eta Model is suitable for paleoclimate studies and provides added value over the driver model.

Este artigo examina a capacidade do conjunto de 40 modelos climáticos do Coupled Model Intercomparison Projects Generation 6 - CMIP6, conjunto MOD, para simular a temperatura do ar e a precipitação médias do período de janeiro de 1985 a dezembro de 2014 em cada estado do Brasil. Apesar dos vieses nas simulações, o subconjunto do CMIP6 conseguiu simular satisfatoriamente o ciclo anual e sazonal da temperatura e precipitação, bem como captar a tendência das variáveis analisadas no Brasil. Em relação a temperatura do ar à superfície, o subconjunto do CMIP6 apresentou o melhor desempenho para as Regiões Sul e Sudeste do Brasil, com destaque para os estados do Paraná, Santa Catarina e São Paulo. O melhor desempenho para a precipitação, com o subconjunto do CMIP6 foi verificado sobre a Região Centro-Oeste. Em relação às tendências de aquecimento no período de 30 anos do estudo, 1985-2014, todos estados do Brasil apresentaram tendência de aquecimento, tanto para os dados do subconjunto do CMIP6, quanto para os dados observados. A precipitação na região Norte e Sudeste, não exibiu tendências claras para o período analisado, alguns estados apresentaram aumento e outros redução da precipitação. Nas Regiões Centro-Oeste e Nordeste todos estados apresentam tendência de redução da chuva. Na Região Sul, os três estados mostram tendência de aumento na chuva tanto no observado quanto no simulado. No entanto, além das incertezas inerentes a modelagem climática e vieses detectados, este estudo é relevante para indicar o comportamento dos modelos em simular o clima presente. A avaliação apresentada neste trabalho estabeleceu níveis de confiança no uso deste subconjunto de simulações de modelos para estudos do clima futuro, conforme detalhado no texto.

In this work, the use of adaptive filters for reducing forecast errors produced by a Regional Climate Model (RCM) is investigated. Seasonal forecasts are compared against the reanalysis data provided by the National Centers for Environmental Prediction. The reanalysis is used to train adaptive filters based on the Recursive Least Squares algorithm in order to reduce the forecast error. The K-means unsupervised learning algorithm is used to obtain the number of filters to employ from the climate variables. The proposed approach is applied to some climate variables such as the meridional wind, zonal wind, and the geopotential height. The forecast is produced by the Eta RCM at 40-km resolution in a domain covering most of Brazil. Results show that the proposed approach is capable of reducing the forecast errors, according to evaluation metrics such as normalized mean square error, maximum absolute error, and maximum normalized absolute error, thus improving the seasonal climate forecasts.

Resumo Simulações climáticas para o clima presente (1960-2005) utilizando o Modelo Climático Regional Eta e o Modelo Hidrológico de Grandes Bacias (MGB), forçado com o Brazilian Earth System Model Ocean-Atmosphere (BESM-AO 2.5) foram realizadas. O objetivo deste trabalho é avaliar o desempenho do Modelo Regional Eta e o Modelo Hidrológico de Grandes Bacias (MGB) na representação dos componentes do balanço de água (precipitação, evapotranspiração, convergência de umidade, vazão, cota e área de inundação) sobre a bacia do rio Madeira. A característica de sumidouro de umidade (P > E) foi simulada pelo modelo regional. Entretanto, o modelo subestimou a precipitação (33%), a evapotranspiração (12%) e a convergência de umidade (6%). O MGB-IPH conseguiu representar o ciclo anual das vazões, níveis do rio (cota) e área de inundação. Também conseguiu reproduzir a translação e amplitude das ondas de cheia, e o atraso de 3 meses entre os máximos da área de inundação e a precipitação sobre a bacia do Madeira. O MGB-IPH mostrou-se uma ferramenta útil para estudos de variabilidade climática, mudanças no clima e no uso da terra, e também para sistemas operacionais de previsão hidrológica na bacia Amazônica. Abstract Downscaling climate simulation for present climate (1960-2005) based on the Eta Regional Climate Model and MGB Large-scale Hydrological Model, forced by Brazilian Model of the Terrestrial System (BESM-AO 2.5), was carried out. The objective of this work is assessment the performance of the Eta regional model and MGB-IPH in the representation of the components of the water budget in Madeira River basin. The moisture sink characteristic (P> E) was simulated by the regional model. In the terrestrial branch, the MGB-IPH hydrological model was able to represent the annual cycle of discharge, water level and floodplain inundation. The performance of the hydrological model and the regional model was satisfactory in the simulation of the seasonal dynamics of hydrological processes and water budget in Madeira river basin, indicating that the hydrological model is a useful tool for studies of climatic variability, changes in climate and land use and for hydrological forecasting operational systems in the Amazon basin.

The natural environment of corn crops is being affected by climate changes. This research is aimed at evaluating the climate change scenarios resulting from the downscaling using the Eta regional climate model, nested in the global model CanESM2, and assessing the consequences of climate changes in the runoff and root water uptake of corn crops in the region of Parana, Brazil. This research also describes the climatology and the possible changes in the climate of the area, according to the different emission scenarios and infer how these changes will affect the dynamics of water in the corn crop in the region, simulated by Hydrus model. Simulations comprise of the historical period (1981–2005) and the future projections under RCP4.5 and RCP8.5, between the years 2046 to 2070. Eta model nested with the global model CanESM2 presented high ability to reproduce the climate in the region. Simulations showed changes in precipitation and an increasing trend of maximum and minimum temperatures when compared with the baseline. The root water uptake showed increasing trends predominantly in the RCP8.5 scenario. These climate changes can strongly affect corn production in the region of Parana, Brazil, as it can lead to increasing runoff and runoff extremes (runoff above 100 mm/day). This situation poses a risk to crop production since it causes losses by leaching and destruction of plants, as well as other factors such as lack of aeration and increased incidence of plant diseases. Similarly, the projected increase in temperature can result in increased evapotranspiration, which affects root water uptake, and the crop water demand.

The objective of this paper is to investigate the influence of soil conditions (initial moisture and soil texture type) on the seasonal simulations of precipitation extremes over Upper São Francisco River basin in Brazil. The Eta regional climate model is used to produce simulations for the dry and rainy seasons in southeast Brazil between the years 1979 and 2012. These are 4.5-month integrations. Two maps of soil texture type and two initial soil moisture conditions are tested. Eta rainfall simulations are more sensitive to soil texture than to the changes in the initial soil moisture. The runs using the map of 26 soil texture types represent better the climate of South America compared to the simulations using the map of 9 soil texture types. In general, the extreme climatic indices and the total accumulated precipitation for the dry and rainy seasons in Brazil are underestimated by the Eta regional climate model over the study region, which suggests the necessity of tests with convection precipitation schemes to improve the model’s performance.

The São Francisco river basin plays a critical role in the hydroelectrical operational planning of Brazil. Understanding the hydroclimatic dynamic regime and, consequently, related climate changes is essential for decision-makers of the hydroelectrical sector. In this context, this work takes the Xingó hydropower plant and its drainage area as a reference for climatic and hydrological analyzes. Observed rainfall in the drainage basin and streamflow measurements in the power plant between 1975 and 2016 are used to assess the climatology of the region and to identify trends in the time series. In addition, a methodological framework based on numerical modeling of the hydroclimatic variables is employed to examine the representation of the present climate (1961 to 1990) and to investigate the future projections (2011 to 2100). The SMAP rainfall-runoff model and the Eta regional climate model nested within two global models are adopted in this investigation under the RCP4.5 and RCP8.5 IPCC scenarios. In Xingó, the average annual precipitation is about 978 mm and the average annual streamflow is 2,534 m³.s− 1. This region is marked by the monsoon cycle, with a clear rainy (October to March) and dry (April to September) period. There is no trend regarding precipitation, while the streamflow time series show a statistically significant decreasing trend in the present climate. Climate projections point to reduction in rainfall and streamflow during the 21st century. The results showed in this work revealed to be crucial to better understand the energy security for Xingó in the present and future climates.

Sao Tome and Principe is a small insular country in the west coast of Central Africa. The small dimensions of the islands and the limited natural resources put these islands under highly vulnerable to climate change. To assess the possible future impacts and risks on their agricultural activities, the high-resolution 4-km downscaled climate change projections using Eta regional climate model are used. A crop risk index (CRI) is proposed to assess the risk of climate change on cocoa (Theobroma cacaoL.), pepper (Piper nigrumL. andPiper guinesseL.), taro (Colocasia esculenta(L.) Schott), and maize (Zea maysL.). The index takes into account the vulnerability to climate conditions and the crop yield in the future, and it is classified intovery-high,high,moderate,low, andvery-low. The climate change projections indicate increase in the risk of taro crop, partly due to thermal stress and partly due to the susceptibility to the leaf blight crop disease in taro. The risk of production of the pepper crop is very-high, mainly due to water stress. In mountain regions, the greater risk is due to the thermal stress caused by low temperatures. The cocoa crop is at risk due to water stress, mainly in the northwestern part of the Sao Tome Island, where major local production occurs. The projection indicates increase of the area with very-high risk to maize crops due to the increase of thermal stress and susceptibility to rust. In addition, in parts of the coastal regions, the risk changed from very-low to high risk, due to the low productivity potential. In general, the risks of the four major crops of Sao Tome and Principe increase in the future climate conditions.

The aim of this work is to present preliminary results of the statistical and dynamical simulations carried out within the framework of the Flagship Pilot Study in southeastern South America (FPS-SESA) endorsed by the Coordinated Regional Climate Downscaling Experiments (CORDEX) program. The FPS-SESA initiative seeks to promote inter-institutional collaboration and further networking with focus on extreme rainfall events. The main scientific aim is to study multi-scale processes and interactions most conducive to extreme precipitation events through both statistical and dynamical downscaling techniques, including convection-permitting simulations. To this end, a targeted experiment was designed considering the season October 2009 to March 2010, a period with a record number of extreme precipitation events within SESA. Also, three individual extreme events within that season were chosen as case studies for analyzing specific regional processes and sensitivity to resolutions. Four dynamical and four statistical downscaling models (RCM and ESD respectively) from different institutions contributed to the experiment. In this work, an analysis of the capability of the set of the FPS-SESA downscaling methods in simulating daily precipitation during the selected warm season is presented together with an integrated assessment of multiple sources of observations and available CORDEX Regional Climate Model simulations. Comparisons among all simulations reveal that there is no single model that performs best in all aspects evaluated. The ability in reproducing the different features of daily precipitation depends on the model. However, the evaluation of the sequence of precipitation events, their intensity and timing suggests that FPS-SESA simulations based on both RCM and ESD yield promising results. Most models capture the extreme events selected, although with a considerable spread in accumulated values and the location of heavy precipitation., Thanks to CORDEX for endorsing the FPS-SESA. This work was supported by the University of Buenos Aires 2018-20020170100117BA grant; JMG, MLB, SAS, RPR funding from the Spanish Research Council (CSIC) I-COOP+ Program “reference COOPB20374”. JMG, JF and AL-G acknowledge support from the Spanish R&D Program through projects MULTI-SDM (CGL2015-66583-R) and INSIGNIA (CGL2016-79210-R), co-funded by the European Regional Development Fund (ERDF/FEDER). AL-G acknowledges support from the Spanish R&D Program through the predoctoral contract BES-2016-078158. Universidad de Cantabria simulations have been carried out on the Altamira Supercomputer at the Instituto de Física de Cantabria (IFCA-CSIC), member of the Spanish Supercomputing Network. MB acknowledges support from the Simons Associateship of the Abdus Salam International Centre for Theoretical Physics. RH acknowledges support from the project LTT17007 funded by the Ministry of Education, Youth, and Sports of the Czech Republic.

The search for data on climate change by researchers, government agencies or private companies is a recurrent demand. However, it is hampered by the means of access to this type of information, mainly due to the complexity of extracting, reformatting, and making this data available, which can exceed terabytes in size. The PROJETA platform aims to automate the process of extracting and making available the dataset of global climate change projections downscaling to 20 km over South America generated by the model Eta at CPTEC/INPE. The data request, processing, and conversion process, which used to be done manually and in a oneto-one data delivery basis. The objective of this work is to describe the methodology used to create the platform PROJETA and the information made available. It is a service that allows access to a broad set of different climatic variables. This dataset is available to different users via the Web or API, in a flexible way in terms of data format and data volume. In addition, it integrates technologies that allow the access to the database in an efficient and easy way for use in studies of impact, vulnerability, and adaptation to climate change in various socio-economic sectors.

Este trabalho analisa as climatologias da temperatura do ar e da precipitação da Bacia do rio Paraíba do Sul (BRPS), localizada na Região Sudeste do Brasil. A precipitação anual varia entre 1000 mm no norte do estado do Rio de Janeiro e 2000 mm sobre a Serra da Mantiqueira. Aproximadamente 80% da precipitação da bacia concentra-se nos meses de outubro a março, sugerindo um regime monçônico na região. A média anual da temperatura média diária varia entre 16°C no extremo sudoeste e 22°C no extremo norte da BRPS. Essa grande variação se deve a localização da BRPS na região de transição entre latitudes médias e tropicais. O efeito da passagem de frentes frias sobre a temperatura e o efeito da atuação da Zona de Convergência do Atlântico Sul sobre a precipitação podem ser observados na distribuição espacial e temporal das variáveis estudadas.

Almost universally, in Regional Climate Modeling (RCM) integrations, Davies’ relaxation lateral boundary conditions are applied. They force variables in a number of rows around the boundary to conform to the driver global model values, completely at the boundary, and less and less toward the inside of the integration domain. Very often, in addition, investigators apply so-called large scale or spectral nudging inside the domain, forcing the integration variables not to depart much from those of the driver model.It is pointed out that there is no scientific basis for these two practices. So why are they used? In particular for the former of these two, it is suggested that reasons must be either a belief that this is a practice RCM should follow, or a technique to address numerical issues of the limited area model used, or a combination of the two. For the latter, a belief only.Examples are shown that, in the absence of these two stratagems, the limited area model can improve on large scales inside its domain. This demonstrates that their use, aimed to force variables inside the domain not to depart much from the driver model data, should be detrimental, if possible numerical issues of the model used were to be remedied.

Resumo O objetivo deste estudo é avaliar o desempenho das simulações por conjunto do modelo Eta-5km do Instituto Nacional de Pesquisas Espaciais para um caso de chuva intensa ocorrido na Bacia do Rio Paraíba do Sul em janeiro de 2000, durante um evento de Zona de Convergência do Atlântico Sul. O conjunto de simulações é formado por 5 membros, denominados de acordo com suas parametrizações convectiva (Betts-Miller-Janjic - BMJ ou Kain-Fritsch - KF) e de microfísica (Ferrier ou Zhao): CNTRL (BMJ/Ferrier); KF (KF/Ferrier); KFMX (KF com fluxo de momentum/Ferrier); KFMXP (KF com fluxo de momentum e força do gradiente da perturbação da pressão/Ferrier) e ZHAO (BMJ/Zhao). As simulações são realizadas com horizontes de 24 até 120 h e condições de contorno inicial e lateral provenientes do “Climate Forecast System Reanalysis”. Os resultados indicam que todos os membros são capazes de posicionar a banda de chuva aproximadamente na mesma localização observada. O modelo, apesar de subestimar os valores das maiores pluviometrias diárias, simula uma frequência maior de eventos de chuva forte. Em geral, a média do conjunto apresenta melhor performance do que cada um dos membros isoladamente e as simulações com 48 h de antecedência são superiores às demais. Abstract The aim of this study is to evaluate the performance of simulations generated by the ensemble of the Eta-5km model from the National Institute for Space Research. The evaluation was performed over the Paraíba do Sul River Basin during an extreme rainfall event, occurred early in January 2000, in a South Atlantic Convergence Zone event. The 5-member ensemble is formed with different convective (Betts-Miller-Jancic - BMJ or Kain-Fritsch - KF) and microphysics (Ferrier or Zhao) parameterizations and are nominated respectively as: CNTRL (Betts-Miller-Janjic/Ferrier); KF (Kain-Fritsch/Ferrier); KFMX (Kain-Fritsch with inclusion of momentum flux/Ferrier); KFMXP (Kain-Fritsch with inclusion of momentum flux and force of the perturbation of pressure gradient/Ferrier) and ZHAO (Betts-Miller-Janjic/Zhao). The simulations are integrated up to 120 h and the initial and boundary conditions were taken from the Climate Forecast System Reanalysis. The results indicate that all members were able to position the rain band in about the same observed location. Although the model underestimates the highest daily precipitation amount, it simulates higher frequency of heavy rainfall events than it really occurs. In general, the ensemble mean simulation presents higher performance than each individual members and the 48-h simulations are better than the other forecast lead times.

Projections of climate change are essential to guide sustainable development plans in the tropical Andean countries such as Peru. This study assessed the projections of precipitation and potential evaporation, rain erosive potential, and precipitation concentration in the Mantaro River Basin, in the Peruvian Andes, which is important for agriculture and energy production in Peru. We assumed the Intergovernmental Panel on Climate Change (IPCC) A1B greenhouse gas emission scenario and simulated the global climate change by the HadCM3 global climate model. Due to the steepness of the mountain slopes and the narrowness of the river valley, this study uses the downscaling of the global model simulations by the regional Eta model down to 20-km resolution. The downscaling projections show decrease in the monthly precipitation with respect to the baseline period, especially during the rainy season, between February and April, until the end of the 21st century. Meanwhile, a progressive increase in the monthly evaporation from the baseline period is projected. The Modified Fournier Index (MFI) shows a statistically significant downward trend in the Mantaro River Basin, which suggests a possible reduction in the rain erosive potential. The Precipitation Concentration Index (PCI) shows a statistically significant increasing trend, which indicates increasingly more irregular temporal distribution of precipitation towards the end of the century. The results of this study allow us to conclude that there should be a gradual increase in water deficit and precipitation concentration. Both changes can be negative for agriculture, power generation, and water supply in the Mantaro River Basin in Peru.

Climate change is one of the greatest issues for human society. The objective of this study is to assess the impacts of future climate change on seasonal average discharge and monthly water budget in a small headwater catchment, located on the Grande River basin, in Minas Gerais, Brazil. The assessment is carried out using the hydrology model, DHSVM. The atmospheric forcing to drive the Distributed Hydrology-Soil-Vegetation Model (DHSVM) is derived from the downscaling of the HadGEM2-ES projections by the Eta Regional Climate Model, at 5-km high resolution. The projections assume the RCP4.5 and RCP8.5 IPCC AR5 emission scenarios. Baseline period was taken between 1961 and 1990. The projections are assessed in three time slices (2011-2040, 2041-2070 and 2071-2099). The climate change is assessed in time slices of 30 years and in comparison against the baseline period to evaluate the hydrological changes in the catchment. The results showed differences in the hydrological behavior between the emission scenarios and though time slices. Reductions in the magnitude of the seasonal average discharge and monthly water budget may alter the water availability. Under the RCP4.5 scenario, results show greater reductions in the water availability in the first time slice, whereas under RCP8.5 scenario greater reductions are indicated in the third time slice.

The Intergovernmental Panel on Climate Change (IPCC) projections of global mean temperature rises are worrisome for coffee crop due to the intolerance of the Arabica species to high air temperature variations. The crop has a large participation in the Brazilian trade balance; therefore, in this study, the impacts of climate change on the potential yield of Arabica coffee (Coffea arabica L.) were assessed in the areas of Southeast Brazil in future climate change scenarios. Simulations of the Eta Regional Climate Model at 5-km resolution used in this study were generated from a second dynamic downscaling of the HadGEM2-ES model runs. The projections adopted two scenarios of greenhouse gas concentration, the RCP4.5 and RCP8.5, and considered the period 2011–2100. The projections indicated a large reduction of about 20 to 60% of the areas currently suitable for coffee cultivation in Southeast Brazil. In the RCP8.5 scenario, at the end of century, coffee cultivation is suitable only in elevated mountain areas, which would pose difficulties to farming management due to the operation of agricultural machinery in mountain areas. In addition, coffee cultivation in these regions could produce environmental impacts in the remnant Brazilian Atlantic Forest. Areas of high climatic risk increase due to temperature increase. The projections showed that the potential yield could be reduced by about 25% by the end of the twenty-first century. These results of potential coffee yield in the future climate indicate a need for adaptation studies of Arabica coffee cultivation.

Sea-level rise (SLR) poses a range of threats to natural and built environments in coastal zones around the world. Assessment of the risks due to exposure and sensitivity of coastal communities to coastal flooding is essential for informed decision-making. Strategies for public understanding and awareness of the tangible effects of climate change are fundamental in developing policy options. A multidisciplinary, multinational team of natural and social scientists from the USA, the UK, and Brazil developed the METROPOLE Project to evaluate how local governments may decide between adaptation options associated with SLR projections. METROPOLE developed a participatory approach in which public actors engage fully in defining the research problem and evaluating outcomes. Using a case study of the city of Santos, in Brazil, METROPOLE developed a method for evaluating risks jointly with the community, comparing ‘no-action’ to ‘adaptation’ scenarios. At the core of the analysis are estimates of economic costs of the impact of floods on urban real estate under SLR projections through 2050 and 2100. Results helped identify broad preferences and orientations in adaptation planning, which the community, including the Santos municipal government, co-developed in a joint effort with natural and social scientists.

This study evaluates the use of tiles to estimate the effects of surface heterogeneities in simulations of local climate in a landscape-fragmented region of Amazonia. Three experiments using the Eta/Noah-MP model were designed as follows: two experiments with a spatial resolution of 5 km with and without the use of the tile approach. The third experiment used a finer spatial resolution of 2 km without the use of the tile approach (high-resolution experiment). Simulations were carried out for the rainy and dry seasons, which correspond to the months of March and September 2003, respectively. In general, the magnitude of surface fluxes is significantly affected by the introduction of tiles. In the dry season, the use of tiles in the simulation increases the magnitude of precipitation (about 7 mm day−1), skin temperature (about 4 °C), sensible heat flux (about 80 W m−2) and surface albedo (about 0.7). It reduces the latent heat flux (about 30 W m−2) and net radiation (about 40 W m−2). On the other hand, in the rainy season, the model produces excessive precipitation. This may have partly masked the signs of the land fragmentation impact. The tile experiment generates a warmer and drier boundary layer during the dry season. The impact of the surface heterogeneity representation is higher in the dry season than in the rainy season. The results suggest that the degree of impact of the subgrid process representation on the local climate is related to the spatial scale of the fragmentation. The use of the tile approach improves the representation of the effects of landscape heterogeneity on the spatial distribution of surface flux variability in fragmented areas. Comparison against measured data from flux towers in the region show that the model can simulate diurnal and seasonal variations in the local fluxes, despite the biases.

This work evaluates the performance of two radiation parameterization schemes in 30-day clear-sky runs of the Eta model over a region in Southeast Brazil. Two versions of the Eta model are compared: a version using the radiation scheme developed by the Geophysical Fluid Dynamics Laboratory (GFDL) and a recently developed version using the Rapid Radiative Transfer Model for GCM (RRTMG). These simulations are compared against CMSAF satellite data and surface station data. The simulation using RRTMG produced downward surface shortwave radiation fluxes closer to observations and reduced the systematic positive bias of the Eta simulation using the GFDL scheme. The 2-m temperature negative bias found in the Eta-GFDL simulations is reduced in the Eta-RRTMG simulations, which results from a larger net total radiation in the Eta-RRTMG simulations. The new version has better accuracy than the Eta using the GFDL scheme for most of the evaluated variables, particularly for clear-sky conditions.

Many natural systems are being affected by regional climate change. Regional climate change may affect the profitability and productivity of corn, which may require changes in the optimum design of drainage systems in the future. Our aim is to determine the effects of regional climate change on the relationship between drain spacing, corn productivity, and profitability and to derive estimates of productivity and profitability until the year 2100 using different future scenarios of climate simulation (CNTRL, HIGH, LOW, and MIDI). Our goal is to optimize drainage system designs that account for changes in climate using different drain spacing and types of soil in Campinas, Brazil. This study also evaluates the performance of the Eta regional climate model to simulate precipitation and air temperature for the study area. Evapotranspiration calculated with the Thornthwaite method (using observed and simulated data) and precipitation data were used as input for the SISDRENA model, which evaluates the performance of one-dimensional drainage systems. As output, the SISDRENA model provides information about drainage system design and indexes of water stress, productivity, and profitability. The general conclusion is that the Eta model is a good tool for studying the effects of climate change in the region because the simulations approximated the observed data. All sets of analyzed years indicated that a spacing of 20 m between drains was best, producing the highest average productivity and profitability. Clay loam soils tended to have higher productivity and profitability than clay soils, which translates to greater profit for the producer. However, the temperature and precipitation variations predicted by the Eta model showed that corn profitability may be reduced, changing the potential productivity in Campinas, Brazil.

Soil degradation by water erosion has been accelerated by human activities. This process is aggravated in the Andes region due to steep slopes, sparse vegetation cover, and sporadic but high intensity rainfall, which together with a shallow soil depth, increases soil erosion risk. The objective of this study was to analyze the soil erosion risk, associated with A1B climate change scenario over the twenty-first century, for the Mantaro River basin (MRB), Peruvian Andes. The temporal analyses revealed maintenance of current soil erosion risk along the twenty-first century in almost all the MRB, whose current risk is either “very severe” or “extremely severe”. At the sub-basin level, for those located in the center and northern MRB, progressive increases were observed in the average erosion rate by the end of this century, increasing the soil erosion risk. In sub-basins under greater influence of the Andes, this risk was classified as “moderate” and remained this way throughout the century, despite the increase in rainfall erosive potential simulated for these. In annual terms, there was a significant trend of decreasing rainfall erosivity and increasing the concentration of rainfall simulated based on A1B climate change scenario. Because the A1B scenario affects rainfall erosivity mainly during the rainy season, this causes a risk to the environmental sustainability and future agricultural activities.

Complex orography of elevated terrain and numerous peaks can act as an important physical barrier to the atmospheric flow and can generate a range of meteorological phenomena. The objective of this study is to investigate the effect of the Brazilian Plateau on the spatial distribution of cold fronts and their climatology for the period between 1979 and 2010 using Climate Forecast System Reanalysis data. The cold fronts are detected and divided into three groups, according to their frequency and trajectory over South America: the continental fronts are referred to as the AN group; the fronts that pass over the coastal region of Sao Paulo are referred to as the SP group; and the fronts that pass over the two areas are referred to as the ANSP group. Composites of means and anomalies of atmospheric variables are constructed for each group. The investigation focuses on the orographic effects of the Brazilian Plateau on the climatology of the cold fronts. The Brazilian Plateau affects the spatial distribution of maximum and minimum frontal frequency. The number of cold fronts over the elevated regions of the Brazilian Plateau is significantly lower than in the surrounding regions. The maximum frontal frequency is found to the east of the Andes and a secondary maximum is found along the Southeast coast of Brazil. The main effect of the Brazilian Plateau on the mean and anomaly fields of meteorological variables is to block the dry and cool post-frontal air at lower atmospheric levels. The most significant anomalies are found in the ANSP group of cold fronts, which are more intense and move more rapidly eastward. On the other hand, the AN cold front group is the most frequent, but the weakest and easily affected by the Brazilian Plateau orography.

Os possíveis impactos sobre os recursos hídricos e a biodiversidade do Cerrado decorrentes da alteração de origem antrópica da concentração de Gases de Efeito Estufa (GEEs) é tida como uma das principais problemáticas ambientais do século XXI. O avanço de pesquisas sobre essa temática é realizado a partir da aplicação de modelos climáticos, que possibilitam a avaliação de cenários exploratórios futuros. Nesse contexto, objetivou-se avaliar as mudanças climáticas projetadas pelo modelo climático regional Eta dirigido pelos modelos globais HadGEM2-ES e MIROC5 para o início (2011-2040) e metade (2041-2070) do século XXI no Estado do Tocantins, para as trajetórias representativas de concentração, RCP 4.5 e RCP 8.5. Levando-se em consideração o regime pluvial inerente ao Tocantins, os resultados foram analisados para as estações chuvosa (de outubro a março) e estiagem (de abril a setembro), tendo sido abordadas as seguintes variáveis: precipitação, evapotranspiração real, temperaturas (média, máxima e mínima) e umidade relativa. A análise das projeções climáticas futuras mostrou possibilidade de severas alterações nos regimes hídrico e térmico no estado do Tocantins nos RCPs 4.5 e 8.5 no século XXI. As projeções de mudanças mais severas de precipitação e temperatura foram pelo Eta-MIROC5 e Eta-HadGEM2-ES, respectivamente, ambas no cenário RCP 8.5. As projeções mostram possibilidade de redução da precipitação de até 524,8 mm.6meses-1 (out-mar) para o início do século XXI, sobretudo para a região Sul. Para as temperaturas (média, mínima e máxima) foram projetadas mudanças positivas em todas as análises. As mudanças mais severas foram para a metade do século XXI, de até 5,1°C para as temperaturas médias, 5,9ºC para as temperaturas máximas e 4,8ºC para as temperaturas mínimas, sobretudo para a região Sudoeste nas proximidades da Ilha do Bananal

Despite the reduction in deforestation rate in recent years, the impact of global warming by itself can cause changes in vegetation cover. The objective of this work was to investigate the possible changes on the major Brazilian biome, the Amazon Rainforest, under different climate change scenarios. The dynamic vegetation models may simulate changes in vegetation distribution and the biogeochemical processes due to climate change. Initially, the Inland dynamic vegetation model was forced with initial and boundary conditions provided by CFSR and the Eta regional climate model driven by the historical simulation of HadGEM2-ES. These simulations were validated using the Santarém tower data. In the second part, we assess the impact of a future climate change on the Amazon biome by applying the Inland model forced with regional climate change projections. The projections show that some areas of rainforest in the Amazon region are replaced by deciduous forest type and grassland in RCP4.5 scenario and only by grassland in RCP8.5 scenario at the end of this century. The model indicates a reduction of approximately 9% in the area of tropical forest in RCP4.5 scenario and a further reduction in the RCP8.5 scenario of about 50% in the eastern region of Amazon. Although the increase of CO2 atmospheric concentration may favour the growth of trees, the projections of Eta-HadGEM2-ES show increase of temperature and reduction of rainfall in the Amazon region, which caused the forest degradation in these simulations. RESUMO: Apesar da redução na taxa de desmatamento nos últimos anos, o impacto do aquecimento global por si só pode causar alterações na cobertura vegetal. O Objetivo deste trabalho foi investigar as possíveis alterações no maior bioma brasileiro, a Floresta Amazônica, levando em consideração diferentes cenários de mudanças climáticas. Os modelos de vegetação dinâmica permitem representar as mudanças na distribuição de vegetação bem como nos processos biogeoquímicos diante de mudanças no clima. Na primeira parte do trabalho, o modelo de vegetação dinâmica Inland foi forçado com condições iniciais e de contorno geradas a partir de dados de reanálise (CFSR) e pela regionalização da simulação histórica de um modelo global do sistema terrestre (HadGEM2-ES) com o modelo Eta. Estas simulações foram validadas utilizando os dados da torre de Santarém-K83. Na segunda parte, avaliou-se o impacto de uma futura mudança climática sobre o bioma floresta através das projeções do modelo Inland forçado com um modelo regional climático. As projeções mostram que algumas áreas de floresta tropical na Amazônia são substituídas por tipo de floresta decídua e pastagem natural no cenário RCP4.5 e apenas por pastagem natural no cenário RCP8.5 no final do século XXI. No Estado do Amazonas, o modelo indica uma redução de cerca de 9% da área de floresta tropical no cenário RCP4.5 e uma redução maior no cenário RCP8.5 de cerca de 50%. Embora o aumento da concentração de CO2 atmosférico possa favorecer o crescimento das árvores, as projeções do modelo Eta-HadGEM2-ES mostram aumento da temperatura e redução da precipitação na região Amazônica, levando a degradação da floresta nestas simulações.

Seasonal rainfall forecasts generated with regional Eta model for the rainy season of the São Francisco River Basin, upstream Hydroeletric Power Plant (HPP) Três Marias in Minas Gerais are evaluated in this work. The use of such forecasts as an input in energy planning models, represent a better management in the generation, transmission and distribution of electricity. However, it is well known that most of the globe, seasonal climate predictability is much reduced, since the effects of boundary conditions to determine the evolution of the average state of the atmosphere compete with internal variability associated with the chaotic instabilities and nonlinear interactions of the atmospheric flow. The forecasts of the Eta-Seasonal-15km model are initiated on days 13 to 17 October, extending until February 28, during the years 2001-2010. The evaluation results indicate that the noise (inter members variability) is higher than the signal (interannual variability), suggesting low reliability of the forecasts for the region during the rainy season. Forecasts of precipitation are underestimated and the Root Mean Square Error of 77.03 mm / month is high, almost twice its standard deviation. Note A high spatial variability of rainfall due to very steep topography, which further reduces the performance of numerical models. A hit rating category of precipitation (IACP), based on the distribution of tertiles, was applied to account for the number of times that the forecasts point to the same category of observed rainfall: rainfall below, within or above the normal range. The IACP for the whole area and during the ten years was low (mean 29%), however in the southern Basin IACP is a bit higher, around 50% to 70% in the Southeast region. The annual review of the forecasts for the entire area indicated that the best model performance occurred in 2005, when conditions ATMS negative in Pacific, near the coast of Peru were persisted in October 2005 and in fact such anomalies occurred through the month of February 2006.

The objective of this work is to assess the impacts of IPCC AR5 climate change scenarios on water resources and hydrological processes across the entire Brazilian territory. Hydrological simulations are carried out in total drainage area of about 11,535,645 km2 and average stream flow of about 272,460 m3/s. The study area consists of different climates and land covers such as the Amazon Forest, Northeast Semiarid, Brazilian Savannah, Pantanal wetlands and temperate climate in the South. The atmospheric forcing to drive the large-scale hydrological model MGB-IPH is derived from the downscaling of two global climate models, HadGEM2-ES and MIROC5, by the Eta Regional Climate Model, at 20 km resolution. The Eta model provided the downscaling of the baseline (1961-1990) and three time-slices (2011-2040, 2041-2070 and 2071-2099). These projections adopted two emission scenarios, the RCP 4.5 and RCP 8.5. The change in the average and extremes of precipitation, evapotranspiration, rates of river discharge and soil moisture were assessed. The simulations showed the response of the hydrographic regions due to change of precipitation and potential evapotranspiration in the scenarios. Water availability decreases in almost the entire study area (exception for the South) and the major basins for hydroelectric power generation are affected. The Northwest, Amazon and a small area along the Northeast Atlantic coast exhibited intensification of the extremes discharges, where the anomaly is positive for high-flow (Q10) and negative for low-flow (Q95). The results highlight the most climatic sensitive regions in Brazil in terms of hydrological variables and water resources.