National Institute for Space Research, Brazil
  • São José dos Campos, São Paulo, Brazil
Recent publications
Mangrove distribution maps are used for a variety of applications, ranging from estimates of mangrove extent, deforestation rates, quantify carbon stocks, to modelling response to climate change. There are multiple mangrove distribution datasets, which were derived from different remote sensing data and classification methods, and so there are some discrepancies among these datasets, especially with respect to the locations of their range limits. We investigate the latitudinal discrepancies in poleward mangrove range limits represented by these datasets and how these differences translate climatologically considering factors known to control mangrove distributions. We compare four widely used global mangrove distribution maps - the World Atlas of Mangroves, the World Atlas of Mangroves 2, the Global Distribution of Mangroves, the Global Mangrove Watch. We examine differences in climate among 21 range limit positions by analysing a set of bioclimatic variables that have been commonly related to the distribution of mangroves. Global mangrove maps show important discrepancies in the position of poleward range limits. Latitudinal differences between mangrove range limits in the datasets exceed 5°, 7° and 10° in western North America, western Australia and northern West Africa, respectively. In some range limit areas, such as Japan, discrepancies in the position of mangrove range limits in different datasets correspond to differences exceeding 600 mm in annual precipitation and > 10 °C in the minimum temperature of the coldest month. We conclude that dissimilarities in mapping mangrove range limits in different parts of the world can jeopardise inferences of climatic thresholds. We expect that global mapping efforts should prioritise the position of range limits with greater accuracy, ideally combining data from field-based surveys and very high-resolution remote sensing data. An accurate representation of range limits will contribute to better predicting mangrove range dynamics and shifts in response to climate change.
Invasive earthworms are threatening soil biodiversity and ecosystem functioning in formerly earthworm-free boreal and temperate forests. Although exotic earthworms are also found in tropical forests, they have received less attention from soil scientists. Here, we summarize data on earthworm populations in the native Brazilian Atlantic Forest (one of the world's 25 biodiversity hotspots) and present a case study on three forests at different regeneration stages, aiming to identify the patterns of exotic species distribution and also the possible consequences of invasive earthworms for soil ecosystem services and macrofauna communities. We found that exotic earthworms, mainly Pontoscolex corethrurus and pheretimoid species (Amynthas corticis and A. gracilis), dominated the earthworm fauna in the native Brazilian Atlantic Forest, while native earthworms were less abundant. Furthermore, we observed that exotic earthworms are probably threatening soil macroinvertebrates, especially detritivores and predators, due to the high soil bioturbation. The widespread occurrence of invasive earthworms in this biome raises concern regarding possible competition with the native soil fauna, including native earthworms, which could dramatically impact ecosystem services linked to soil, especially those related to climate regulation and water storage.
The present article aims to experimentally observe the flame propagation of ethanol–air mixtures in a tube closed at both ends with an aspect ratio of 27.68. The mixtures were prepared with equivalence ratios ranging from 0.8 to 1.1. The tests were performed for initial pressures of 20, 40, and 60 kPa. The phenomenon of flame front inversion was observed in all experiments. This phenomenon is also known as tulip flame. It was also observed that the flame front inverted several times at the equivalence ratios of 1.0 and 1.1. After the initial deceleration, the velocity oscillated with a high amplitude at these equivalence ratios. An analysis of the available experimental data was performed to better understand the conditions that allow the flame velocity oscillations to occur. It was found that these oscillations manifest when the following conditions are met: (a) closed channels, (b) sufficiently high laminar flame velocity and (c) sufficiently high aspect ratio. Moreover, this phenomenon is coupled with pressure waves that develop inside the duct. The relationship between the distance for the formation of the flattened flame front and the laminar flame velocity was used to define a characteristic time that correlates with the available experimental data.
In this Review, we compare rates of anthropogenic and natural environmental changes in the Amazon and South America and in the larger Earth system. We focus on deforestation and carbon cycles because of their critical roles on the Amazon and Earth systems. We found that rates of anthropogenic processes that affect Amazonian ecosystems are up to hundreds to thousands of times faster than other natural climatic and geological phenomena. These anthropogenic changes reach the scale of millions of square kilometers within just decades to centuries, as compared with millions to tens of millions of years for evolutionary, climatic, and geological processes.
Approximately 2.5 × 106 square kilometers of the Amazon forest are currently degraded by fire, edge effects, timber extraction, and/or extreme drought, representing 38% of all remaining forests in the region. Carbon emissions from this degradation total up to 0.2 petagrams of carbon per year (Pg C year-1), which is equivalent to, if not greater than, the emissions from Amazon deforestation (0.06 to 0.21 Pg C year-1). Amazon forest degradation can reduce dry-season evapotranspiration by up to 34% and cause as much biodiversity loss as deforestation in human-modified landscapes, generating uneven socioeconomic burdens, mainly to forest dwellers. Projections indicate that degradation will remain a dominant source of carbon emissions independent of deforestation rates. Policies to tackle degradation should be integrated with efforts to curb deforestation and complemented with innovative measures addressing the disturbances that degrade the Amazon forest.
The oceanic South Atlantic Convergence Zone (SACZ) has played a major role during South America’s 2021/2022 summer extreme rainy season, being responsible for more than 90% of the precipitation in some regions of Southeast Brazil and in some regions of the Southwestern Atlantic Ocean (SWA). The summer of 2021/2022 was unique and rare and considered an abnormally humid season as verified by official Brazilian Institutes. First, the unusual number of cases of SACZ episodes (seven), was the highest recorded in the last decade. Second, all the cases that occurred were oceanic SACZ that assumed characteristics of an Atmospheric River and produced an excessively anomalous amount of precipitation during this period. Excess precipitation along with the regions located in mountainous and very uneven relief, which by orographic effects favors high precipitation volumes, were responsible for amplifying the observed impacts, such as landslides and floods that caused several losses to society. We also showed the main effects of coupling and interaction between the waters of the surface layer of the SWA and the atmosphere. Our learning from this study ends with the unprecedented results of how the marine atmospheric boundary layer (MABL) is locally modulated by the sea surface temperature (SST) that lies just below it. Until the present moment, we emphasize that this important mechanism has not been widely highlighted in the literature, showing that even though the ocean is colder than before oceanic SACZ is established, it is still warmer than the overlying air, thus, the ocean continues to be an active source of heat and moisture for the atmosphere and enhances the MABL instability process.
Polypropylene (PP)/talc composites are used extensively in the automotive, aeronautical, and consumer goods industries; however, the increasing demand for more efficient, safe, and less environmentally impact materials makes it necessary to include new reinforcements. In this way, the use of graphene nanoplates (GNP) is a good alternative because this carbon‐based material allows the achievement of new multifunctional nanocomposites with improved properties and process optimization. In this work, PP/talc (80/20) composites were prepared with the addition of 1, 3, 5, and 7 wt% of GNP using the extrusion process and injection molding. Morphological, thermal, rheological, mechanical, electrical, and electromagnetic characterizations were performed. The addition of GNPs led to a linear reduction in the melt flow index (MFI) of the samples. A rheological percolation was observed in the sample with the addition of 7 wt% of GNP. The addition of 5 and 7 wt% of GNP led to significant increases in elastic modulus and Shore D hardness. The electrical and electromagnetic evaluation showed that the increase of GNP in the compositions contributed to improvements in electrical conductivity and permittivity, resulting in a proportional increment in the total attenuation component (SET).
Monitoring changes in tree cover for assessment of deforestation is a premise for policies to reduce carbon emission in the tropics. Here, a U-net deep learning model was used to map monthly tropical tree cover in the Brazilian state of Mato Grosso between 2015 and 2021 using 5 m spatial resolution Planet NICFI satellite images. The accuracy of the tree cover model was extremely high, with an F1-score >0.98, further confirmed by an independent LiDAR validation showing that 95% of tree cover pixels had a height >5 m while 98% of non-tree cover pixels had a height <5 m. The biannual map of deforestation was then built from the monthly tree cover map. The deforestation map showed relatively consistent agreement with the official deforestation map from Brazil (67.2%) but deviated significantly from Global Forest Change (GFC)’s year of forest loss, showing that our product is closest to the product made by visual interpretation. Finally, we estimated that 14.8% of Mato Grosso’s total area had undergone clear-cut logging between 2015 and 2021, and that deforestation was increasing, with December 2021, the last date, being the highest. High-resolution imagery from Planet NICFI in conjunction with deep learning techniques can significantly improve the mapping of deforestation extent in tropical regions.
Introduction The productivity of the Amazon Rainforest is related to climate and soil fertility. However, the degrees to which these interactions influence multiannual to decadal variations in tree diameter growth are still poorly explored. Methods To fill this gap, we used radiocarbon measurements to evaluate the variation in tree growth rates over the past decades in an important hyperdominant species, Eschweilera coriacea (Lecythidaceae), from six sites in the Brazilian Amazon that span a range of soil properties and climate. Results Using linear mixed-effects models, we show that temporal variations in mean annual diameter increment evaluated over a specific time period reflect interactions between soil fertility and the drought index (SPEI-Standardized Precipitation and Evapotranspiration Index). Discussion Our results indicate that the growth response of trees to drought is strongly dependent on soil conditions, a facet of forest productivity that is still underexplored, and which has great potential for improving predictions of future tropical tree growth in the face of projected climate change.
Modification to the law-of-the wall represented by a dimensionless correction function $\phi_{RSL}(z/h)$ is derived using near-neutral atmospheric turbulence measurements collected at two sites in the Amazon in near-neutral stratification, where $z$ is the distance from the forest floor and $h$ is the mean canopy height. The sites are the Amazon Tall Tower Observatory (ATTO) for $z/h\in [1,2.3]$ and the Green Ocean Amazon (GoAmazon) site for $z/h\in[1,1.4]$. A link between the vertical velocity spectrum $E_{ww}(k)$ ($k$ is the longitudinal wavenumber) and $\phi_{RSL}$ is then established using a co-spectral budget (CSB) model interpreted by the moving-equilibrium hypothesis (MEH). The key finding is that $\phi_{RSL}$ is determined by the ratio of two turbulent viscosities and is given as $\nu_{t,BL}/\nu_{t,RSL}$, where $\nu_{t,RSL}=(1/A)\int_{0}^{\infty}\tau(k) E_{ww}(k)dk$, $\nu_{t,BL}=\kappa (z-d) u_*$, $\tau(k)$ is a scale-dependent decorrelation time scale between velocity components, $A=C_R/(1-C_I)=4.5$ is predicted from the Rotta constant $C_R=1.8$ and the isotropization of production constant $C_I=3/5$ given by Rapid Distortion Theory, $\kappa$ is the von K\'arm\'an constant, $u_*$ is the friction velocity at the canopy top, and $d$ is the zero-plane displacement. Because the transfer of energy across scales is conserved in $E_{ww}(k)$ and is determined by the turbulent kinetic energy dissipation rate ($\epsilon$), the CSB model also predicts that $\phi_{RSL}$ scales with $L_{BL}/L_d$, where $L_{BL}$ is the length scale of attached eddies to $z=d$, $L_d=u_*^3/\epsilon$ is a macro-scale dissipation length.
This Research Topic aimed to improve our understanding of the physical and biogeochemical processes linking the South Atlantic to other ocean basins and within the Atlantic as a whole through oceanic or atmospheric teleconnections. The South Atlantic plays an essential role in the climate of the adjacent continental areas and actively contributes to the Atlantic Meridional Overturning Circulation (AMOC), hence modulating the world's climate. The Atlantic, Pacific and Indian basins interact with each other in a two-way fashion, mainly through the tropics at the seasonal to multidecadal scales. Although not fully understood at present, the physical and biogeochemical processes involved in this interbasin interaction are essential to be addressed when we aim to increase our ability to predict the planet's weather and climate. The present volume of Frontiers in Marine Science contains ten original research articles put together by 42 different authors from 12 countries in Europe, the Americas, Asia and Africa. This special issue widens our knowledge of the South Atlantic variability, which still falls behind other ocean basins. The authors used all existing observing systems in the South and Tropical Atlantic Ocean: PIRATA ocean-atmosphere mooring array, Argo and other autonomous drifting ocean sensors, and satellite products reprocessed over the last four decades. They also took advantage of up-to-date ocean and atmospheric reanalyzes and dedicated numerical simulations. Even though this special issue lacked papers that directly linked the Atlantic to other ocean basins on short scales, the contribution is of paramount importance and paved the way for new research. We expect that this special issue will inspire future generations of scientists interested in studying the South Atlantic and the role of the tropical and South Atlantic on interbasin climate variability in support of the Climate and Ocean -Variability, Predictability, and Change Program (CLIVAR).
Introduction: Water treatment deficit and poor health, hygiene and sanitation infrastructure can contribute to disease transmission by dissemination of contaminants and microorganisms. As an alternative, carbon-based materials coated with antimicrobial molecules have been proposed for water treatment, but few supporting data are available so far. Hence, this study investigates the potential use of PAN-based activated carbon fibers (ACF) decorated with silver nanoparticles in water treatment. Methods: Silver nanoparticles were incorporated into the material using a cheap and electroless method. Field emission scanning electron microscopy (FEGSEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) characterized the whole material. The textile was mounted on a water filter prototype and had its capacity to remove bacterial (Escherichia coli) and fungal ( Candida albicans , Aspergillus niger and Penicillium funiculosum ) cells evaluated. Composition and toxicity of the filtered water were determined. Results: Water filtered by Ag@ACF for 2 and 24 h contained 0.254 mg/L and 0.964 mg/L Ag, respectively. Ag@ACF filtering successfully removed E. coli , C. albicans , and A. niger from the suspensions, but not P. funiculosum . Treated water was non-toxic for Vero cells and Drosophila melanogaster, but toxic for Raphidocelis subcapitata. Ag@ACF showed efficient microbial elimination when applied in water treatment. Silver nanoparticles released in aqueous medium may be responsible for R. subcapitata toxicity. Future studies should be conducted to reduce silver nanoparticles release from the carbon fiber.
In this work, the Amazonian native acai fruit, a superfruit recognized worldwide, was used through a simple operation of maceration in alcohol vinegar to transform it into an attractive and functional product containing the acai natural colorant and its bioactive compounds. The variables studied were the proportion of alcohol vinegar to acai (8:2 and 1:1) and maceration period (7, 14, and 21 days). The final vinegar was subjected to the determination of color parameters, antioxidant capacity (DPPH, ABTS), total phenolics content (TPC), volatile compounds extracted by stir bar sorptive extraction and identified by gas‐chromatography–mass spectrometry analysis. The alcohol vinegars macerated with acai presented the color according to the content of acai added and maceration period employed, whereas antioxidant capacity and TPC were comparable to vinegars elaborated from fruits and red wine. Sixty volatiles compounds classified into five chemical groups were identified. The principal volatile compounds which contributed to the aroma in the products were 3‐methyl‐1‐butanol, phenylethyl alcohol, benzaldehyde, o‐cymene, p‐cymenene, isoamyl acetate, and ethyl acetate. The most attractive product regarding the parameters studied was obtained from the use of the proportion of 1:1 of alcohol vinegar:acai and maceration period of 14 days. This product retained the most similar color to acai in natura, the highest values for antioxidant capacity measured by ABTS and TPC while being rich in volatile compounds due to the contributions mainly of alcohols, esters, aldehydes, and terpenes. This work demonstrates the feasibility to produce an alcohol vinegar with an attractive color and functional properties by the addition of acai resulting in to a wide spectrum of chemical compounds of acai through a very simple operation of maceration during 14 days of a proportion of 1:1 of alcohol vinegar:acai.
The strategy for assessing simulations produced by climate models established as part of the Atmospheric Model Intercomparison Project (AMIP) delivers an outline for model analysis, verification/validation, and intercomparison. Numerical models are continuously being developed to find the best representation for the amount and distribution of precipitation in Brazil to improve the country’s precipitation forecast. This article describes the key features of the Brazilian Global Atmospheric Model (BAM) (developed by the Center for Weather Forecasting and Climate Studies of the National Institute for Space Research (CPTEC/INPE)) and analyses of its performance for annual rainfall climate simulations. This study considered the representation of the annual precipitation in Brazil mainly during the rainy season in the central part of Brazil by the BAM. The model was run over the 1990 to 2015 period using spectral Eulerian model dynamics with a 70-horizontal resolution of approximately 1.0◦ × 1.0◦ and 42 vertical sigma levels. The analysis was divided into two stages: the annual precipitation and the rainy season precipitation. Model precipitation analyses were performed using statistical methods, such as the mean and standard deviation, comparing modeled data with observed data from two datasets, data from the XAV (observed data from INMET, ANA, and DAEE), and the Climate Prediction Center (CPC). In general, the BAM model simulations reasonably replicated the configuration of the spatial distribution of precipitation in the Brazilian territory almost entirely, especially compared with the XAV. The accumulated precipitation in the southern region presented great variation, accumulating from 750 mm year−1 in the extreme south to 1750 mm year−1 in the north of this region. Average values of the BAM accumulated precipitation ranged from 1000 to 2000 mm year−1, within the expected average, compared to observed values of 750–1500 mm year−1 (CPC and XAV, correspondingly). Although there was an underestimation of the accumulated precipitation by the model, the model reasonably reproduced the precipitation during the rainy season. The performed assessment identified model aspects that need to be improved.
In this study, we evaluated the performance of the Brazilian Global Atmospheric Model (BAM), in its version 2.2.1, in the representation of the surface variables solar radiation, temperature (maximum, minimum, and average), and wind speed. Three experiments were carried out for the period from 2016 to 2022 under three different aerosol conditions (constant (CTE), climatological (CLIM), and equal to zero (ZERO)), discarding the first year as a spin-up period. The observations came from a high-resolution gridded analysis that provides Brazil with robust data based on observations from surface stations on a daily scale from 1961 to 2020; therefore, combining the BAM outputs with the observations, our intercomparison period took place from 2017 to 2020, for three timescales: daily, 10-day average, and monthly, targeting different applications. In its different simulations, BAM overestimated solar radiation throughout Brazil, especially in the Amazon; underestimated temperature in most of the northeast, southeast, and south regions; and overestimated in parts of the north and mid-west; while wind speed was only not overestimated in the Amazon region. In relative terms, the simulations with constant aerosol showed better performance than the others, followed by climatological conditions and zero aerosol. The dexterity indices applied in the intercomparison between BAM and observations indicate that BAM needs adjustments and calibration to better represent these surface variables. Where model deficiencies have been identified, these can be used to drive model development and further improve the predictive capabilities.
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1,426 members
Maria Cristina Forti
  • Center for Earth Systems Science
Alber Ipia
  • Remote Sensing Division
Diogenes Salas Alves
  • C.G. Observ. Terra - OBT/DPI; PG-SER; PG-CST
Aline de Matos Valerio
  • Remote Sensing Division
Claudio Clemente Faria Barbosa
  • Divisão de Processamento de Imagens (DPI)
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