Publicações

Intraseasonal rainfall variability of the South American monsoon system is characterized by a pronounced dipole between southeastern South America and southeastern Brazil. Here we analyze the dynamical properties of extreme rainfall events associated with this dipole by combining a nonlinear synchronization measure with complex networks. We make the following main observations: (i) Our approach reveals the dominant synchronization pathways of extreme events for the two dipole phases, (ii) while extreme rainfall synchronization in the tropics is directly driven by the trade winds and their deflection by the Andes mountains, extreme rainfall propagation in the subtropics is mainly dictated by frontal systems, and (iii) the well-known rainfall dipole is, in fact, only the most prominent mode of an oscillatory pattern that extends over the entire continent. This provides further evidence that the influence of Rossby waves, which cause frontal systems over South America and impact large-scale circulation patterns, extends beyond the equator. Key PointsComplex networks substitute EOFs for spatial analysis of extreme rainfallReveal drivers of extreme rainfall related to South American rainfall dipoleExtreme events controlled by Rossby oscillation extending over the entire continent.

Despite increased intellectual and conceptual consideration of the linkages between ecosystem service (ES) provisions and poverty alleviation (PA) globally, there has been limited analysis of how these paradigms are used and framed in the regional context of policy-making. In this paper, we address this question by eliciting perspectives on the historical evolution of policies addressing the environment and poverty nexus in the Brazilian Amazon. Our analysis is twofold. First, through an analysis of policy context, we explore how multilateral and international programs have influenced and helped shape national and regional policy-making in the Amazon. Second, through our analysis of policy content, we provide an in-depth discussion of key ES and/or PA policies implemented in the Amazon. Furthermore, we analyze the operationalization of the policy, describe management options, and highlight their impacts on ES and PA. Our results show dichotomies between environmental programs and their social effectiveness, and between environmental and developmental agendas. More recently, however, some attempts have been made at delivering ES protection and PA jointly in policy-making. In conclusion, we provide a framework for policy analysis that can be applied to other tropical countries in the world. If Brazil is to keep its leading role in addressing the challenges of maintaining ecosystem service provision, while alleviating poverty in the Amazon, it must learn from its own experiences.

As land use change (LUC), including deforestation, is a patchy process, estimating the impact of LUC on carbon emissions requires spatially accurate underlying data on biomass distribution and change. The methods currently adopted to estimate the spatial variation of above- and below-ground biomass in tropical forests, in particular the Brazilian Amazon, are usually based on remote sensing analyses coupled with field datasets, which tend to be relatively scarce and often limited in their spatial distribution. There are notable differences among the resulting biomass maps found in the literature. These differences subsequently result in relatively high uncertainties in the carbon emissions calculated from land use change, and have a larger impact when biomass maps are coded into biomass classes referring to specific ranges of biomass values. In this paper we analyze the differences among recently-published biomass maps of the Amazon region, including the official information used by the Brazilian government for its communication to the United Nation Framework on Climate Change Convention of the United Nations. The estimated average pre-deforestation biomass in the four maps, for the areas of the Amazon region that had been deforested during the 19902009 period, varied from 205 ± 32 Mg ha−1 during 19901999, to 216 ± 31 Mg ha−1 during 20002009. The biomass values of the deforested areas in 2011 were between 7 and 24 % higher than for the average deforested areas during 19901999, suggesting that although there was variation in the mean value, deforestation was tending to occur in increasingly carbon-dense areas, with consequences for carbon emissions. To summarize, our key findings were: (i) the current maps of Amazonian biomass show substantial variation in both total biomass and its spatial distribution; (ii) carbon emissions estimates from deforestation are highly dependent on the spatial distribution of biomass as determined by any single biomass map, and on the deforestation process itself; (iii) future deforestation in the Brazilian Amazon is likely to affect forests with higher biomass than those deforested in the past, resulting in smaller reductions in carbon dioxide emissions than expected purely from the recent reductions in deforestation rates; and (iv) the current official estimate of carbon emissions from Amazonian deforestation is probably overestimated, because the recent loss of higher-biomass forests has not been taken into account.

Ionospheric scintillation refers to amplitude and phase fluctuations in radio signals due to electron density irregularities associated to structures named ionospheric plasma bubbles. The phenomenon is more pronounced around the magnetic equator where, after sunset, plasma bubbles of varying sizes and density depletions are generated by plasma instability mechanisms. The bubble depletions are aligned along Earth’s magnetic field lines, and they develop vertically upward over the magnetic equator so that their extremities extend in latitude to north and south of the dip equator. Over Brazil, developing bubbles can extend to the southern peak of the Equatorial Ionization Anomaly, where high levels of ionospheric scintillation are common. Scintillation may seriously affect satellite navigation systems, such as the Global Navigation Satellite Systems. However, its effects may be mitigated by using a predictive model derived from a collection of extended databases on scintillation and its associated variables. This work proposes the use of a classification and regression decision tree to perform a study on the correlation between the occurrence of scintillation at the magnetic equator and that at the southern peak of the equatorial anomaly. Due to limited size of the original database, a novel resampling heuristic was applied to generate new training instances from the original ones in order to improve the accuracy of the decision tree. The correlation analysis presented in this work may serve as a starting point for the eventual development of a predictive model suitable for operational use. Key Points Analyzes correlation between scintillation occurrence at different stations Includes the selection of attributes for the proposed correlation analysis Employs decision tree to analyze the correlation of scintillation occurrences.

Evapotranspiration (E) in the Amazon connects forest function and regional climate via its role in pre-cipitation recycling However, the mechanisms regulating water supply to vegetation and its demand forwater remain poorly understood, especially during periods of seasonal water deficits In this study, we efficiencyaddress two main questions: First, how do mechanisms of water supply (indicated by rooting depth andgroundwater) and vegetation water demand (indicated by stomatal conductance and intrinsic water useefficiency) control evapotranspiration (E) along broad gradients of climate and vegetation from equatorialAmazonia to Cerrado, and second, how do these inferred mechanisms of supply and demand compareto those employed by a suite of ecosystem models? We used a network of eddy covariance towers inBrazil coupled with ancillary measurements to address these questions With respect to the magnitudeand seasonality of E, models have much improved in equatorial tropical forests by eliminating most dryseason water limitation, diverge in performance in transitional forests where seasonal water deficits aregreater, and mostly capture the observed seasonal depressions in E at Cerrado However, many mod-els depended universally on either deep roots or groundwater to mitigate dry season water deficits, therelative importance of which we found does not vary as a simple function of climate or vegetation In addi-tion, canopy stomatal conductance (gs) regulates dry season vegetation demand for water at all exceptthe wettest sites even as the seasonal cycle of E follows that of net radiation In contrast, some models sim-ulated no seasonality in gs, even while matching the observed seasonal cycle of E. We suggest that canopydynamics mediated by leaf phenology may play a significant role in such seasonality, a process poorlyrepresented in models Model bias in gsand E, in turn, was related to biases arising from the simulatedlight response (gross primary productivity, GPP) or the intrinsic water use efficiency of photosynthesis(iWUE). We identified deficiencies in models which would not otherwise be apparent based on a simplecomparison of simulated and observed rates of E. While some deficiencies can be remedied by parame-ter tuning, in most models they highlight the need for continued process development of belowgroundhydrology and in particular, the biological processes of root dynamics and leaf phenology, which via theircontrols on E, mediate vegetation-climate feedbacks in the tropics.

In their seminal lightning studies using streak cameras, Schonland et al. (1938) identified four negative stepped leader events that they term β2, a rather rare variant of the type β leader, and in it, the second and slower stage of the leader is associated with the appearance of one or more fast dart streamers, which travel rapidly down from the cloud along the previously formed track and cease when they have caught up with the slower leader tip. Seven negative downward leaders that agreed with the description given by Schonland et al. for type β2 were recorded in Tucson, Arizona, USA, and in São José dos Campos, São Paulo, Brazil. All cases were recorded by a high-speed camera operating at 4000 frames per second, and electric field changes were measured for three of them. Their dart streamers had speeds between 106 and 107 m s−1, compatible with previous observations of recoil leaders (RLs). Also, during the development of the three cases with correlated electric field changes, it was possible to identify sequences of microsecond-scale pulses preceding the propagation of a dart streamer in the channel. It is proposed that the luminous process that occurs during the development of a type β2 stepped leader is the visible manifestation of one or more RLs that begin inside the cloud and connect to the in-cloud, positive portion of the bipolar, bidirectional leader, and then travel downward to the lower end of the negative stepped leader path.

A Economia Verde (EV) é um assunto emergente no contexto das discussões científicas e políticas mundiais, tendo como principal desafio tornar as atividades econômicas em atividades sustentáveis. A cadeia produtiva da cana-de-açúcar envolve questões sociais, econômicas e ambientais controversas. Assim, o objetivo deste trabalho foi avaliar a adequação aos princípios da EV da cultura em questão na microrregião de Ribeirão Preto/SP. Para tanto, foi desenvolvido o Índice de Adaptabilidade à Economia Verde (IAEV), o qual é composto por Índices Parciais (Impacto Econômico IPIE; Impacto Social IPIS; e Impacto Ambiental IPIA). A construção de tais índices baseou-se em variáveis disponibilizadas por órgãos como IBGE, SUS, SEADE e CANASAT/ INPE. De forma geral, a microrregião apresentou uma melhoria no IAEV em uma década (2000 e 2010). Além disso, constatou-se que os índices parciais social e ambiental apresentaram os menores valores, sendo considerados como aspectos prioritários para futuros investimentos. ABSTRACT: The Green Economy (GE) is an emerging issue in the context of scientific and political wide discussions. Its main challenge is to turn economic activities into sustainable activities. The production chain of cane sugar involves social, economic and environmental aspects controversial. Thus, the aim of this study was to evaluate the adjustment with the principles of EV of the culture in question in the microregion of Ribeirão Preto (SP). Therefore, we developed the Index Adaptability to the Green Economy (IAGE), which consists of Partial Indexes (Economic Impact PIEI; Social Impact PISI, and Environmental Impact PIEI). The construction of such indexes was based on variables provided by agencies such as IBGE, SUS, SEADE and CANASAT/INPE. In general terms, the microrregion in study presented an improvement in IAGE in a decade (2000 and 2010). We also demonstrate that the social and environmental partial indexes were the lowest values; priority areas for future investments.

Our review focuses on the projections of climate change in the Brazilian semiarid region, the Caatinga, based on recent publications about global climate change and biology. We found several vulnerable points in the initial estimates, the main one being that the data were collected and analyzed without a multidisciplinary knowledge. This review discusses several studies that show the current knowledge in many semiarid regions around the world. Some of these studies argue for the increase in vegetation greenness responses even under severe and prolonged drought, based on the high resilience the Caatinga native species show under severe drought conditions over the years. Additionally, we include in this review recent data produced by our group on key ecophysiological variables under drought conditions. We also show successful examples of deforested areas recovery in the semiarid region of the Central America. It is critical that the recovery of semiarid areas is coupled with the implementation of socio-environmental policies, engaging the local population and providing subsidies for life wealth improvement. These are key aspects for a long-term recovery and conservation of the Brazilian dry tropical forest.

According to the State Program of Action to Combat Desertification and Mitigate the Effects of Drought (PAE/CE), the State of Ceara-Brazil has three centers configured with Areas Susceptible to Desertification which are the Hinterlands of Inhamuns, the Hinterlands Irauçuba and Center North and the Hinterlands of Medium Jaguaribe, encompassing twelve municipalities and covering a total area of 26,432,65km2. It is known that the problem of desertification in State of Ceara acquired more notoriety from the Arid Project which subsidized actions such as the elaboration of the National Program of Action to Combat Desertification and Mitigate the Effects of Drought. Since then, although with a smaller intensity than expected, noted that strategies to combat the phenomenon is being implemented in the State. In this context, the objective of this study is to conduct a systematization of the major Plans, Policies and Programs (PPP) in the State of Ceara in the period from 2004 to 2012. To this end, documentary and bibliographic searches were carried out. The systematization was made taking as parameters: objective of intervention, implementation year, managing agency, participation of society, geographical area, obstacles faced and benefits from the results obtained. It was found that the low participation, the supervision of PPP and reduced integration between policies are factors that limit the implementation and the control of actions.

As interest grows in the contribution of ecosystem services to poverty alleviation, we present a new conceptual framework, synthesizing insights from existing frameworks in social-ecological systems science and international development. People have differentiated abilities to benefit from ecosystem services, and the framework places emphasis on access to services, which may constrain the poorest more than aggregate availability. Distinctions are also made between categories of ecosystem service in their contribution to wellbeing, provisioning services and cash being comparatively easy to control. The framework gives analytical space for understanding the contribution of payments for ecosystem services to wellbeing, as distinct from direct ecosystem services. It also highlights the consumption of ecosystem services by external actors, through land appropriation or agricultural commodities. Important conceptual distinctions are made between poverty reduction and prevention, and between human response options of adaptation and mitigation in response to environmental change. The framework has applications as a thinking tool, laying out important relationships such that an analyst could identify and understand these in a particular situation. Most immediately, this has research applications, as a basis for multidisciplinary, policy-relevant research, but there are also applications to support practitioners in pursuing joint policy objectives of environmental sustainability and poverty alleviation.

The carbon and water cycles for a southwestern Amazonian forest site were investigated using the longest time series of fluxes of CO2 and water vapor ever reported for this site. The period from 2004 to 2010 included two severe droughts (2005 and 2010) and a flooding year (2009). The effects of such climate extremes were detected in annual sums of fluxes as well as in other components of the carbon and water cycles, such as gross primary production and water use efficiency. Gap-filling and flux-partitioning were applied in order to fill gaps due to missing data, and errors analysis made it possible to infer the uncertainty on the carbon balance. Overall, the site was found to have a net carbon uptake of approximate to 5 t C ha(-1) year(-1), but the effects of the drought of 2005 were still noticed in 2006, when the climate disturbance caused the site to become a net source of carbon to the atmosphere. Different regions of the Amazon forest might respond differently to climate extremes due to differences in dry season length, annual precipitation, species compositions, albedo and soil type. Longer time series of fluxes measured over several locations are required to better characterize the effects of climate anomalies on the carbon and water balances for the whole Amazon region. Such valuable datasets can also be used to calibrate biogeochemical models and infer on future scenarios of the Amazon forest carbon balance under the influence of climate change.

This paper introduces a lightning forecasting method called Potential Lightning Region (PLR), which is the probability of the occurrence of lightning over a region of interest. The PLR was calculated using a combination of meteorological variables obtained from high-resolution Weather Research and Forecasting (WRF) model simulations during the summer season in southeastern Brazil. The model parameters used in the PLR definition were: surface-based Convective Available Potential Energy (SBCAPE), Lifted Index (LI), K-Index (KI), average vertical velocity between 850 and 700 hPa (w), and integrated ice-mixing ratio from 700 to 500 hPa (QICE). Short-range runs of twelve non-severe thunderstorm cases were performed with the WRF model, using different convective and microphysical schemes. Through statistical evaluations, the WRF cloud parameterizations that best described the convective thunderstorms with lightning in southeastern Brazil were the combination of Grell-Devenyi and Thompson schemes. Two calculation methods were proposed: the Linear PLR and Normalized PLR. The difference between them is basically how they deal with the influence of lightning flashes over the WRF domain’s grid points for the twelve thunderstorms analyzed. Three case studies were used to test both methods. A statistical evaluation lowering the spatial resolution of the WRF grid into larger areas was performed to study the behavior and accuracy of the PLR methods. The Normalized PLR presented the most suitable one, predicting flash occurrence appropriately.