Publicações

Brazil ranks in third place within the top 10 renewable electricity producers with almost 80% of the electricity generated from renewable sources. This work describes the status of solar and wind energy resource assessment at Centre for Earth System Science (CCST) of Brazilian Institute for Space Research (INPE) and also the major efforts of the to provide reliable information. It describes the recent studies in development by Renewable Energy team at CCST/INPE in numeric modeling in order to provide reliable resource assessment in order to provide the information demands of Brazilian energy sector.

In 1997 scientists proposed an agenda for biogeochemical research in river corridors of the Amazon basin to both identify gaps in knowledge and to outline a possible approach to filling those gaps. Most previous research in the Amazon had focused on natural processes with a majority of effort on the main stem and its largest tributaries; much less was known about the small river corridors at both the micro (<100 ha) and meso (<100,000 ha) scale or the riparian forests or floodplains around these rivers. In addition, although many potential impacts on rivers and floodplains from anthropogenic land cover or land use conversion were proposed little empirical data were available. A nested sampling design from micro- to macro-scale was proposed. Over the intervening 13 years of research as part of the Largescale Biosphere Atmosphere project in Brazil much new information has been gained. Many studies at the small watershed scale demonstrated clear impacts on stream water flow paths from groundwater to surface water due to forest loss. In addition, processes controlling chemical composition were advanced including surface interflow and in-stream processing. At the meso-scale distributed hydrologic models successfully captured human influence on river process. At the macro-scale carbon processing from land to water was further elucidated, particularly with the extent and activity of flood inundated areas. The lag in response from small watershed to the macro-basin remains a pressing question. Similarly, the role of impoundments or climate change on flood stage and floodplain function needs further consideration.

The study of atmospheric trace gases is increasing over the years. One of these gases is sulfur dioxide (SO2), which is found in the troposphere and stratosphere, as a result of both natural and anthropogenic emissions. A campaign was made in Cubatao-SP, from 04/12/2007 to 08/07/2007, to measure the total column of this gas with a Brewer Spectrophotometer. With this instrument the total column of SO2 was calculated. Since this region is highly industrialized, high total columns of SO2 were expected, which indeed occurred, with a daily average of 6.4 DU during the whole period.

This paper reviews recent progress in our understanding of the American on the functioning and variability of the South American Monsoon System (SAMS), in time scaling varying from synoptic to long term variability and climate change, from paleoclimatic time scales (The Mid Holocene) to the future. The SAMS contains one of the most prominent summertime climate patterns in South America, featuring a strong seasonal variability in a region lying between the Amazon and the La Plata Basin Much of the recent progress is derived from complementary international programs, such as the Monsoon Experiment South America (MESA), as well as on ongoing international programs such as the Large Scale Biosphere Atmosphere Experiment in the Amazon Basin LBA,CLARIS LPB Europe-South America Network for Climate Change Assessment and Impact Studies in La Plata Basin Project and the Past Global Changes program PAGES, where assessments of atmosphere-land surface interactions, the role of land use changes and aerosols from biomass burning are considered as sources of variability and change in the SAMS functioning, characteristics and behavior. This region is particularly susceptible to climate variability due to the dependence of local economies on agricultural activities and hydroelectricity generation. Also addressed are the past and future climate change simulations and projections and extremes in the SAMS region, which are important for impact and vulnerability assessments. This discussion includes the need to identify and understand important processes that control the monsoonal climate, and how these processes may vary, change, and interact with key societal sectors, including water resource management, hydroelectric generation, agriculture and agribusiness. Recent advances in understanding the SAMS include new insights into moisture transport processes between the tropics and extratropics; a description of the structure and variability of low level jets; a definition of the role of remote and local forcing; and resolution of the diurnal cycle of precipitation and convection in the core monsoon regions.

This work describes the implementation of an automated water quality monitoring network designed for operation at the Paraíba do Sul river, Brazil. Equipments, sensors and telecommunications systems, engineering solutions, site selection factors for the water-quality stations and the minimal requirements for operation were analyzed and specified. A set of preliminary data collection graphics are presented as example to demonstrate the application.

In the past few decades, the role of natural and human-induced fire regimes and disturbances have received considerable attention in ecosystem studies. Most investigations focus on anthropogenic fire disturbances particularly associated to tropical degradation in South America, mostly due to cropland and pastureland expansion. Although human-triggered fires practically overcome the effects of natural fire events in this tropical zone, understanding and modeling the natural dynamics of the forest-savanna transition remain an open issue particularly because tropical savannas and tropical forests may occur under the same climatic envelope in portions of this tropical region. In this context, a simple and conceptual climate-vegetation-natural fire (CVNF) model is proposed to investigate the role of natural fires on forest-savanna transition dynamics in tropical South America. Quantitative results of this model support ecological theories and observational evidences, suggesting that lightning-triggered fires play a significant role in determining the location of the tropical forest-savanna boundary in South America. Our model calculations suggest that in the absence of fires, tropical forests would extend about 300 km into the presently-observed savanna domain.

During LBA/BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) field experiment, measurements of several trace gases and aerosols were made onboard INPE’s “Bandeirante aircraft”. Flights transected the Amazon basin from the Tropical Atlantic Ocean shore to the northwestern part of the Amazon basin, passing over a variety of ecosystems from the surface to an altitude of about 5 km in two different periods. Phase A was in November 2008, during transition from dry to wet season, with rainfall to the west and south of Manaus, but much drier conditions with widespread vegetation fires in the eastern and northern Amazonia. Phase B occurred during the opposite transition, from wet to dry season, when the ITCZ was located over the equator, abnormally south of its normal position in May, favoring events of northern hemisphere inflow to the Amazon basin. Precipitation was above average and fires only occurred far to the south. Here, we examine the observations of ozone through comparison with mixing ratios simulated by CCATT-BRAMS, a non-hydrostatic and fully compressible mesoscale chemistry-transport model, aiming to use the model results to assess the ozone budget in the Amazonia during these two different periods. The observed ozone zonal gradient across the basin below 700 mb was analyzed through the relative contribution of precursors emissions from urban, biomass burning and biogenic sources, as well as chemical production and loss, dry deposition and convective transport mechanisms.

The Amazon biome provides multiple environmental services, of which maintaining water cycles, conserving carbon stocks and biodiversity are among the most important. This biome system is under threat and often seen as extremely vulnerable. Several lines of evidence, however, suggest that the system contains a degree of resilience to threats such as deforestation, economic demands and climate change. Rather, functioning of the biome services may remain robust until thresholds, or tipping points, are reached beyond which high vulnerability can shift the whole Amazon system into a different regime, such as a savanna state. We have investigated a selection of the feedbacks that are associated with such resilience. For this we investigated the 1) fate of wet valley bottoms in the face of drying, 2) the evaporative power, maintaining the water cycle, of fragmented deforestation landscapes, 3) the local drivers of deforestation and how these respond to climate and 4) the feedbacks in large-scale and international drivers and possible development scenarios for the Amazon region. The emerging picture provides a still incomplete, but linked conceptual model of Amazon resilience. Our results shows that evapotranspiration from fragmented landscapes is likely not lower, maybe even higher than that of pristine forests. This means robustness of the water cycle but possibly implies local water stress, which will be exacerbated by climatic drying. Apart from this it is known that fragmentation enhances biodiversity loss and fire risk, but we did not study that here. If wet landscape elements such as valley swamps will be stressed they will loose soil carbon as well as nutrients, therefore reducing their biomass. On the other hand economic strength and access are the main drivers for further deforestation in small-scale land-use change, while it is insensitive to climate change. At large scales the advance of agriculture into the Amazon is driven by economic demand, nationally as well as internationally, and sensitive to environmental concerns through both government regulation and consumer pressure. A key physical uncertainty is the response of agriculture to reduced rainfall, because depending on geographical region reduced rainfall may be beneficial to crops and pastures, but only down to a certain optimum value. A key socio-economic factor in the future of the Amazon is consumer behaviour, which is in principle very sensitive to environmental concern. This critically depends on whether science will be able to convey a consensus-based, clear, simple but also really effective advice on how the world can best help the Amazon region to stay robust and far removed from tipping points.