Publicações

Tropical forests are an important part of global water and energy cycles, but the mechanisms that drive seasonality of their land-atmosphere exchanges have proven challenging to capture in models. Here, we (1) report the seasonality of fluxes of latent heat (LE), sensible heat (H), and outgoing short and longwave radiation at four diverse tropical forest sites across Amazonia-along the equator from the Caxiuana and Tapajos National Forests in the eastern Amazon to a forest near Manaus, and from the equatorial zone to the southern forest in Reserva Jaru; (2) investigate how vegetation and climate influence these fluxes; and (3) evaluate land surface model performance by comparing simulations to observations. We found that previously identified failure of models to capture observed dry-season increases in evapotranspiration (ET) was associated with model overestimations of (1) magnitude and seasonality of Bowen ratios (relative to aseasonal observations in which sensible was only 20%-30% of the latent heat flux) indicating model exaggerated water limitation, (2) canopy emissivity and reflectance (albedo was only 10%-15% of incoming solar radiation, compared to 0.15%-0.22% simulated), and (3) vegetation temperatures (due to underestimation of dry-season ET and associated cooling). These partially compensating model-observation discrepancies (e.g., higher temperatures expected from excess Bowen ratios were partially ameliorated by brighter leaves and more interception/evaporation) significantly biased seasonal model estimates of net radiation (R-n), the key driver of water and energy fluxes (LE similar to 0.6 R-n and H similar to 0.15 R-n), though these biases varied among sites and models. A better representation of energy-related parameters associated with dynamic phenology (e.g., leaf optical properties, canopy interception, and skin temperature) could improve simulations and benchmarking of current vegetation-atmosphere exchange and reduce uncertainty of regional and global biogeochemical models.

Agricultural systems play a key role in achieving many of the Sustainable Development Goals, established by the United Nations, given the current challenge of producing enough food to feed a global population that is expected to reach 10 billion people by 2050. More efficient and sustainable use of nutrients in agriculture is an important step to increasing production while minimizing threats to natural ecosystems and resource depletion. In this study, we developed a system nutrient balance for nitrogen (N) and phosphorus (P) to evaluate nutrient use practices in cropping and grazing systems in the Vermelho River watershed (VRW), Upper Pantanal, Brazil, and investigated options to improve N and P use efficiency (NUE and PUE). Our results show P balance in cropping systems are positive while those in grazing systems tend to be negative. The positive values in cropping systems are due to both high P inputs from mineral fertilizers and high soil P-sorbing capacities. The negative values in grazing systems are a result of the removal of animal products without replacing the nutrients. Most of the N inputs in the crops grown in this region come from biological nitrogen fixation. The NUE in cropping systems is about 0.95, which is higher than the upper critical value of the desirable range (0.60.9). Given the high NUE value and the risk of soil mining, improving cropping systems NUE by adjusting the inputs to replenish N outputs and avoid soil erosion in the VRW are of considerable interest.

One of the most crucial parts of solid waste management is determining landfill site location, since multiple factors must be considered and there is no universal formula. The main purpose of this study is to make a worldwide systematic review of restriction criteria used for landfill siting using geographic information systems (GIS). Literature from the last years was thoroughly assessed, and 45 restrictions found were classified as environmental, economic, or social criteria. Our findings show that although the number of articles published has increased recently, they use on average seven restrictions, focusing mainly on environmental over economic and social criteria. In our boxplot statistical analysis, the most frequently used environmental restrictions are the distance from surface water resources (used in 77% of articles), slope (52%), and distance from groundwater founts (40%), with a median of 300 m, 20%, and 250 m, respectively. The most frequently used economic restrictions are distances from roads (60%), airports (40%), and power lines (18%), with medians of 275 m, 3000 m, and 75 m, respectively. The most frequently used social restrictions are distances from urban areas (45%), settlements and residential areas (40%), and cultural heritage or archaeological areas (23%), with medians of 1000 m. This information might help, on the one hand, governments to develop new legislation about landfill siting and on the other hand, decision-makers and scientists to produce new studies with different restrictive scenarios.

The Amazon Basin is at the center of an intensifying discourse about deforestation, land-use, and global change. To date, climate research in the Basin has overwhelmingly focused on the cycling and storage of carbon (C) and its implications for global climate. Missing, however, is a more comprehensive consideration of other significant biophysical climate feedbacks [i.e., CH4, N2O, black carbon, biogenic volatile organic compounds (BV0Cs), aerosols, evapotranspiration, and albedo] and their dynamic responses to both localized (fire, land-use change, infrastructure development, and storms) and global (warming, drying, and some related to El Nino or to warming in the tropical Atlantic) changes. Here, we synthesize the current understanding of (1) sources and fluxes of all major forcing agents, (2) the demonstrated or expected impact of global and local changes on each agent, and (3) the nature, extent, and drivers of anthropogenic change in the Basin. We highlight the large uncertainty in flux magnitude and responses, and their corresponding direct and indirect effects on the regional and global climate system. Despite uncertainty in their responses to change, we conclude that current warming from non-CO2 agents (especially CH4 and N2O) in the Amazon Basin largely offsets- and most likely exceeds-the climate service provided by atmospheric CO2 uptake. We also find that the majority of anthropogenic impacts act to increase the radiative forcing potential of the Basin. Given the large contribution of less-recognized agents (e.g., Amazonian trees alone emit similar to 3.5% of all global CH4), a continuing focus on a single metric (i.e., C uptake and storage) is incompatible with genuine efforts to understand and manage the biogeochemistry of climate in a rapidly changing Amazon Basin.

The Paraguaçu River is one of the most important rivers in Bahia State, Brazil, and the main tributary of the Todos os Santos Bay, the second largest in that country. We evaluated the spatio-temporal variations in the composition and structure of the phytoplankton community in the Paraguaçu River estuary as influenced by rainfall and fluvial discharge from the Pedra do Cavalo dam. Bi-monthly collections were carried out from May 2018 to March 2019 at 12 sampling stations in the estuary. During this period, phytoplankton samples, water samples to determinate the concentration of dissolved inorganic nutrients and data on salinity, temperature, pH, dissolved oxygen, and water transparency were collected. Data on rainfall and dam discharge were also obtained. Abiotic variables and chlorophyll-a showed significant differences in the estuary zones, and silicate concentrations demonstrated differences between the dam discharge periods. A total of 194 phytoplankton taxa were identified, with diatoms showing the highest densities and diversities throughout the study period. Cyclotella meneghiniana, Nitzschia sp., and Scrippsiella acuminata formed blooms in the dry season, whereas blooms of Planktothrix isothrix occurred in the rainy season and during a period of medium dam discharge in the dry season. The influence of dam discharge was quite evident, with increases in nutrient concentrations in the estuary during the months of higher flow that altered the composition and density of the phytoplankton communities in the different system zones. The formation of blooms in response to increased nutrient availability represents an increase in the primary productivity of the system, although blooms of potentially harmful species (such as Planktothrix isothrix) may represent a risk to human activities in the region.

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.

Green-blue infrastructure in urban regions guarantees the provision of resources such as water, energy, and food, which are interdependent and fundamental in ensuring human development. In this study, we analyzed the environmental injustice issue relationships of the supply and production of water, energy, and food in the Sao Paulo Macrometropolis, Brazil. Its 180 municipalities were compared and categorized ~ into losers and winners based on the urban nexus approach, the proportion of green infrastructure, and human development. We applied a neural network self-organizing map to official publicly available data to obtain clusters of municipalities featuring combinations of 19 indicators. The results showed four clusters with three containing characteristics of receivers (Capital, Hinterland, and Developed Receivers) and one of providers, the latter aggregating municipalities with a strong role in providing water, food, and subsidies for energy generation. However, the providers also included the municipalities that had the greatest inequities in terms of human development and social inclusion. The importance of evaluating the co-benefits of green-blue infrastructure in urban spaces can serve as an adaptation strategy to both improve natural resource management and offer support to different processes and ecosystem functions. Our study provides a comprehensive understanding of complex urban systems by considering environmental justice and nexus synergies.

While wind power is a low-carbon renewable energy technology with relatively little land footprint, the necessary infrastructure expansion still has land-related environmental impacts. Brazil has seen more than a ten-fold increase in wind power capacity in the last decade. However, little is known about these impacts of wind power generation in Brazil compared to other world regions, although Brazilian wind power infrastructure is concentrated in the least protected ecosystems that are prone to degradation, desertification and species extinction. This study focuses on land-use impacts of past wind power generation development in four Brazilian federal states, covering 80% of the country’s installed capacity. We assessed their spatial installation patterns, associated land-use and land cover change in the period before installation until 2018, and potential alternative installation locations, using a detailed wind turbine location database in combination with a high-resolution land-use and land cover map. In contrast to wind parks built in Europe, we found that 62% of the studied wind park area was covered by native vegetation and coastal sands. Overall, 3.2% of the total wind cluster area was converted from native vegetation to anthropogenic use. Wind parks installed mainly on native vegetation, on average, underwent higher land-use change compared to other wind parks. As Brazil intends to more than double its current wind power capacities by 2029, we explored possibilities to reduce environmental risks due to wind power expansion. We showed that this is feasible by integrating wind parks into human-altered areas, as sufficient wind resources there are available.

This study presents an assessment of the ability of the Hadley Centre Global Environment Model version 2-Earth system configuration (HadGEM2-ES)-in simulating the mid-latitude storm tracks over the Southern Hemisphere (SH). The storm tracks are primarily assessed using cyclone tracking using data from a 4 member ensemble of 27-year simulations of HadGEM2-ES over the historical period, and the European Centre for Medium-Range Weather Forecasts Interim Reanalysis. Both winter and summer periods are considered and contrasted. Results show that the storm track (ST) climatology of HadGEM2-ES presents similar patterns to those of the reanalysis. However, the model tends to represent the austral winter ST position with an equatorward bias and a zonal bias in the spiral towards the pole. The main differences were found during the austral winter, with large track density biases over the Indian Ocean indicating a poor representation of the ST in this specific region. This was found to be related to two factors. First, the large negative genesis biases over South America, Antarctic Peninsula and the Antarctic coast. Second, the model resolution and the representation of the Andes Mountains in South America. The link between STs and the large-scale circulation is examined and shows at upper levels an equatorward jet position bias of the subtropical jet and a negative bias in the eddy-driven, associated with a large cold bias over the extratropical and polar regions. The analysis of the large-scale circulation shows that the split jet during winter has problems in the model linked to these biases, including geopotential anomaly and sea surface temperature biases. Consequently, in general the track densities over the Southern oceans are underestimated in the austral winter. During summer, the results show the STs move poleward and there is a single eddy-driven jet, which is represented relatively well compared with the winter situation. These factors tend to reduce the differences seen in the cyclone track distribution biases. Although the model has biases in the ST behaviour in the SH it is still considered that these do not preclude this model being used for perturbation and future projection studies.

Peatlands are carbon-rich ecosystems that cover 185423 million hectares (Mha) of the earth’s surface. The majority of the world’s peatlands are in temperate and boreal zones, whereas tropical ones cover only a total area of 90170 Mha. However, there are still considerable uncertainties in C stock estimates as well as a lack of information about depth, bulk density and carbon accumulation rates. The incomplete data are notable especially in tropical peatlands located in South America, which are estimated to have the largest area of peatlands in the tropical zone. This paper displays the current state of knowledge surrounding tropical peatlands and their biophysical characteristics, distribution and carbon stock, role in the global climate, the impacts of direct human disturbances on carbon accumulation rates and greenhouse gas (GHG) emissions. Based on the new peat extension and depth data, we estimate that tropical peatlands store 152288 Gt C, or about half of the global peatland emitted carbon. We discuss the knowledge gaps in research on distribution, depth, C stock and fluxes in these ecosystems which play an important role in the global carbon cycle and risk releasing large quantities of GHGs into the atmosphere (CO2 and CH4) when subjected to anthropogenic interferences (e.g., drainage and deforestation). Recent studies show that although climate change has an impact on the carbon fluxes of these ecosystems, the direct anthropogenic disturbance may play a greater role. The future of these systems as carbon sinks will depend on advancing current scientific knowledge and incorporating local understanding to support policies geared toward managing and conserving peatlands in vulnerable regions, such as the Amazon where recent records show increased forest fires and deforestation.

The spectral impact on various PV materials eamorphous silicon (a-Si), CdTe, CIGS, single crystalline silicon (sc-Si) and multi crystalline (mc-Si)e in two nearby cities of Southeastern Brazil is presented. For every PV technology studied, the values of the spectral mismatch factor on instantaneous, monthly and annual basis were computed by means of spectra recorded over a 12-month experimental campaign carried out in S~ ao Paulo and S~ ao Jose dos Campos. A blue-biased however seasonal spectrum prevails in both cities, which leads to annual spectral gains of up to around 6% and 2% exhibited by a-Si and CdTe, respectively. On the other hand, CIGS, sc-Si and mc-Si show negligible annual gains that lie between around 1% and 0%. These results are well aligned with previous findings obtained using both experimental and modelled spectra in other low-latitude sites with tropical climate. Consequently, spectral effects cannot be ignored in such sites, especially when modelling the outdoor behavior of larger bandgap PV devices. Last, a quasi-linear relationship exists between the monthly average photon energy and the monthly spectral mismatch factor for all the PV materials under scrutiny. This conclusion is in good agreement with previous works carried out in mid-latitude sites.

Here we present a global and regionally resolved terrestrial net biosphere exchange (NBE) dataset with corresponding uncertainties between 20102018: Carbon Monitoring System Flux Net Biosphere Exchange 2020 (CMS-Flux NBE 2020). It is estimated using the NASA Carbon Monitoring System Flux (CMS-Flux) topdown flux inversion system that assimilates column CO2 observations from the Greenhouse Gases Observing Satellite (GOSAT) and NASAs Observing Carbon Observatory 2 (OCO-2). The regional monthly fluxes are readily accessible as tabular files, and the gridded fluxes are available in NetCDF format. The fluxes and their uncertainties are evaluated by extensively comparing the posterior CO2 mole fractions with CO2 observations from aircraft and the NOAA marine boundary layer reference sites. We describe the characteristics of the dataset as the global total, regional climatological mean, and regional annual fluxes and seasonal cycles. We find that the global total fluxes of the dataset agree with atmospheric CO2 growth observed by the surface-observation network within uncertainty. Averaged between 2010 and 2018, the tropical regions range from close to neutral in tropical South America to a net source in Africa; these contrast with the extra-tropics, which are a net sink of 2.5 ± 0.3 Gt C/year. The regional satellite-constrained NBE estimates provide a unique perspective for understanding the terrestrial biosphere carbon dynamics and monitoring changes in regional contributions to the changes of atmospheric CO2 growth rate. The gridded and regional aggregated dataset can be accessed at https://doi.org/10.25966/4v02-c391 (Liu et al., 2020).