Publicações

This research aims to analyze two easterly wave disturbance events that reached the east coast of Northeast Brazil (NEB) on 15 May 2005 and 20 June 2006. The performance of the regional Eta Model was evaluated through four sets of experiments using different horizontal resolutions (10 and 40 km) and convective parameterization schemes [BettsMillerJanjic´ (BMJ) and KainFritsch (KF)]. Through analysis of 700-hPa wind fields, all experiments, with 40- and 10-km horizontal resolutions and using the BMJ and KF schemes, were shown to well represent a trough propagating westward from about 208Wto NEB, with a 5-day forecast range. When evaluating the model sensitivity to different convective parameterizations, all the experiments showed similar results and underestimated rainfall in most of the domain. The obtained results suggest the need to extend this analysis to a larger number of cases and to test other cumulus parameterizations in order to improve the rainfall forecast in eastern NEB.

Severe hydrological droughts in the Amazon have generally been associated with strong El Niño events. More than 100 years of stage record at Manaus harbour confirms that minimum water levels generally coincide with intense warming in the tropical Pacific sea waters. During 2005, however, the Amazon experienced a severe drought which was not associated with an El Niño event. Unless what usually occurs during strong El Niño events, when negative rainfall anomalies usually affect central and eastern Amazon drainage basin; rainfall deficiencies in the drought of 2005 were spatially constrained to the west and southwest of the basin. In spite of this, discharge stations at the main-stem recorded minimum water levels as low as those observed during the basin-wide 19961997 El Niño-related drought. The analysis of river discharges along the main-stem and major tributaries during the drought of 20042005 revealed that the recession on major tributaries began almost simultaneously. This was not the case in the 19961997 drought, when above-normal contribution of some tributaries for a short period during high water was crucial to partially counterbalance high discharge deficits of the other tributaries. Since time-lagged contributions of major tributaries are fundamental to damp the extremes in the main-stem, an almost coincident recession in almost all tributaries caused a rapid decrease in water discharges during the 2005 event.

In this study we developed a methodology to identify and quantify the relationships among determinants of land cover change using a regional case study in the Brazilian Amazon. The method is based on the application of fuzzy cognitive maps (FCMs), a semi-quantitative tool that provides a structured assessment of key feedbacks in sce- nario analysis. Novel to the application of FCMs is the use of spatial data-sets as the main input to build a cognitive map. Identification of interactions between land cover determinants and strengths is based on an empirical analysis of spatially explicit data and literature review. Expert knowledge is adopted to identify the strengths and weak- nesses of the method. Potential pitfalls, such as spatial autocorrelation and scale issues, identified are intrinsic to the empirical data analysis. The outputs of the resulting FCMs are compared to the outputs of spatially explicit models under similar scenarios of change. The proposed method is said to be robust and reproducible when compared with participatory approaches, and it can endorse the consistency between demand and allocation in scenario analysis to be used in spatially explicit models.

Este artigo apresenta um estudo de verificação das previsões de chuva de um sistema de previsão do tempo por ensemble regional. O conjunto é composto por seis membros, dos quais quatro utilizam o modelo RAMS 6.0 e dois usam o WRF 3.1, inicializados com dados dos modelos globais do CPTEC ou GFS e diferentes parametrizações de convecção. A verificação foca nas previsões de chuva de 24, 48 e 72 horas e nos limiares de precipitação de 1mm, 5mm e 10mm sobre o Estado do Ceará. Os membros do ensemble apresentaram resultados superiores à persistência em todo o domínio avaliado. O modelo RAMS apresenta maior índice de acerto, principalmente no litoral norte do Estado, porém um maior falso alarme em comparação com o modelo WRF. O sistema de previsão de chuva diminui sua qualidade com o aumento dos horizontes e a intensidade da chuva que se quer prever.

A study was performed to evaluate the surface soil moisture derived from Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) sensor observations over South America. Other soil moisture and rainfall datasets were also used for the analysis. The information for the soil data came from the Eta regional climate model, and for the rainfall data from the Tropical Rainfall Microwave Mission (TRMM) satellite. Statistical analysis was used to evaluate the quality of the soil moisture and rainfall products, with estimates of the correlation coefficient (R), χ2 and Cramer’s phi (φc). The results show high correlations (R > 0.8) of the AMSR-E soil moisture products with the Eta model for different regions of South America. Comparison of soil moisture products with rainfall datasets showed that the AMSR-E C-band soil moisture product was highly correlated with the TRMM satellite rainfall datasets, with the highest values of χ2 and φ. The results show that the AMSR-E C-band soil moisture products contain important information that can be used for various purposes, such as monitoring floods or droughts in arid areas or as input within the framework of an assimilation scheme of numerical weather prediction models.

O estudo trata da caracterização morfológica do aerossol Black Carbon (BC) coletado durante os meses de março a novembro de 2008 num ponto de monitoramento em São José dos Campos-SP. O aerossol BC é um particulado inerte na atmosfera, porém, devido à sua porosidade e natureza adsortiva, atua como superfície ativa de algumas reações químicas heterogêneas, podendo estar saturado com espécies tóxicas ou carcinogênicas. Assim, aerossóis de BC podem representar um perigo para a saúde pública, além de serem considerados o segundo maior contribuinte para o aquecimento global, em termos de sua forçante radiativa direta. A técnica utilizada foi a Microscopia Eletrônica de Varredura (MEV) associada à Espectroscopia de Energia Dispersiva de raios X (EDX). Essa técnica também permite a análise qualitativa da composição elementar das partículas. A partir de classificação, por semelhança morfológica, foram identificados 6 grupos distintos de partículas: um grupo de partículas produzidas por combustão de motores; outro de partículas procedentes da ressuspensão do solo; grupo de partículas da queima de biomassa; de partículas de fuligem industrial e mais dois grupos com morfologia e composição química semelhantes e específicos da região. As principais fontes identificadas foram de combustão de motores e ressuspensão do solo, porém com influências de outras fontes naturais e antrópicas.

Seahorses (Hippocampus spp.) are globally threatened by overexploitation and habitat destruction; they are also regarded as susceptible to heavy exploitation due to some of their life-history traits. From an economic perspective, they are fishes with high monetary value and marketability. Seahorses are now listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), to ensure that the international trade is not detrimental to the survival of wild populations; the effectiveness evaluation of these international controls needs comparable monitoring data, including evaluation of spatial and temporal trends. This study assesses the seahorse trade in Brazil, aiming to detect trends in catch levels, volumes and prices. Our main findings were: the dried trade was unregulated, without formal records, and primarily domestic, although records of unreported exports existed; it was primarily sustained by incidental captures in trawl nets. The live seahorse trade was mainly destined for exports, and regulated through national quotas. Between 2002 and 2009, mean prices for dried seahorses ranged from US$1.06 +/- 0.46 (level 1 traders) to US$2.78 +/- 0.68 (end-sellers) each, while mean prices for each live seahorse traded on the domestic market (1997-2009) ranged from US$1.13 +/- 0.02 (level 1 traders) to US$10.08 +/- 1.71 (retailers). Mean declared export price (2006-2008) was 15.57 +/- 10.87. Enhanced implementation of the CITES listing in Brazil will require further research, and additional measures to address both direct and indirect fishing pressure on seahorse populations.

Os raios podem interferir e até comprometer temporariamente o sucesso de qualquer programa espacial. Acidentes com raios no setor aeroespacial, atualmente, são raros, em função das precauções tomadas nos centros de lançamento.

Com as alterações do clima, tempestades e ventanias serão cada vez mais frequentes, o que tornará mais vulneráveis as linhas de transmissão aéreas de energia distribuídas pelo Brasil.

The year 2010 began with an El Niño event well stablished in the Pacific Ocean. A rapid transition took place and La Niña was present by July. The La Niña event in 2010 one of the strongest on record. The El Niño-to-La Niña transition was similar to the event occurring in 1998, another very warm year, although El Niño was weaker and La Niña stronger in 2010. The annual mean temperature and total precipitation were mainly near normal across the region.

After the drought of 2005, drought struck the Amazon region again in 2010. Drier-than-normal conditions were observed in northwestern, central, and eastern Amazonia during austral summer and the rest of Amazonia until the end of the year. Below-normal rainfall and warm temperatures affected the water level of the Rio Negro River, which reached its lowest level since record keeping began 107 years ago. The drier conditions also favored the forest fires in southern Amazonia; the number of fires reported by September was about 200% higher compared to 2009.

The concept of global ecosystem services has become a powerful paradigm for understanding the link between ecosystem processes and related human activities, which is expressed by the economic and ecological quantification of the services in regards to sustainable development. The role of tropical forests in the global climate system and the uncertainty of the exact magnitude of this complex interaction has become a major concern to the scientific community. In this paper we review and synthesize the global effects of Amazon deforestation in Brazil, as well as drivers and challenges related to this process. To this end, we provide data on carbon emissions from combined annual maps of clear cutting of primary forests and spatial information on biomass distribution for different vegetation types and secondary vegetation growth, as well as the temporal dynamic related to the deforestation process and its interregional heterogeneity, the social and institutional drivers. In 2009, during the Conference of Parties, of the United Nation Framework Convention on Climate Change (Copenhagen, Denmark), Brazil announced a voluntary commitment to reduce the national GHG emissions by 2020 and, to this end, such commitment requires reducing Amazon rainforest deforestation by 80% over a decade. To achieve this target, a set of consolidated remote sensing techniques have served to monitor and calculate the extent of deforestation, which became indispensable auditing tools for conservation, forest restoration and implementing climate change mitigation schemes.