Desenvolvimento de Metodologia para Validação e Análise de dados de dióxido de enxofre (so2) Atmosférico sobre o Continente Sul-Americano

This work describes the development of a methodology for validating the use of Brewer spectrophotometer for measuring the SO2 total columns, from adaptations in its original calculation algorithm. The results obtained show the possibility of using Brewer spectrophotometer to measure the total columns of sulfur dioxide, with a gain in data quality, of great help to understand the behavior of this gas in the atmosphere with observations that can be used for model validation and calibration of satellites.Este trabalho mostra o desenvolvimento de uma metodologia para validar o uso do espectrofotômetro Brewer na medição das colunas totais de SO2, a partir de adaptações em seu algoritmo original de cálculo. Os resultados obtidos revelam a possibilidade de uso do espectrofotômetro Brewer para medir as colunas totais de dióxido de enxofre, com ganho na qualidade dos dados, de grande auxílio para o conhecimento do comportamento deste gás na atmosfera, com observações que podem ser utilizadas para validação de modelos e calibração de satélites

Analysis of the influence of environmental parameters on methane flux from floodplains and lakes in the Abobral River, Pantanal, Brazil

This study evaluates the influence of physical and chemical characteristics of the water column in the processes that result in methane emissions in the Pantanal. Two surveys were conducted in 2009 and 2010, corresponding to the drought and flood seasons, respectively. The CH4 fluxes were determined using the static chamber technique. Environmental variables, such as depth, water temperature, pH, redox potential, dissolved oxygen and total dissolved solids were also measured. Diffusive and bubble flux presented an average value of 11.1 ± 13.5 mg CH4 m-2 d-1 e 275.9 ± 348.5 mg CH4 m-2 d-1, which is a value near those observed in other tropical flooded regions. Statistical t-tests have shown significant differences between drought and flood seasons (p ≤ 0.05). Diffusive fluxes represented about 87% of the total fluxes measured in drought. During the flood season there were more instances of bubble fluxes (77%). Statistical analysis (correlation and Principal Components Analysis) indicate that physical and chemical characteristics could affect methane fluxes. Diffusive fluxes correlated mainly with pH, redox potential and dissolved oxygen, which is in accordance with the increase of organic matter during flooding. Bubble fluxes measured during the drought season correlated mainly with water depth and temperature, pH and redox potential, which is an indication of an environment to suitable to the formation and liberation of the bubbles from sediment

Influence of physicochemical water characteristics in the transport of methane to the atmosphere at Rodrigo de Freitas lagoon, RJ

The accumulation and decomposition of organic matter in water bodies can increase the potential emission of greenhouse gases to the atmosphere. In this study, in a prospective and exploratory way, we evaluated the relationship between physicochemical characteristics of water on the transport of methane to the atmosphere at Rodrigo de Freitas lagoon, RJ. In 2011, campaigns were carried out in which 200 samples were collected for analysis of superficial methane emission and 30 water samples were collected to verify the dissolution of this gas in the water column, measuring simultaneously both the physicochemical water parameters along this column. The methane flow measurements showed that this lagoon is a source methane emission to the atmosphere with an average flux of 33 ± 10 mgCH4m-2d-1. The evaluation of limnological parameters that could affect the emission flux revealed that the water depth and temperature were the most influential factors in this process. A profile analysis of methane in the water column suggests the existence of a higher concentration of this gas in the region of the sedimentary strata at the bottom of the lagoon. However, the potential emission may not reach the surface, possibly due to the decrease in the rate of vertical diffusion of methane, as a result of the increase of pressure with depth and the presence of methanotrophic bacterias that consume methane throughout the water column