Variação espacial e temporal da irradiância solar e da razão entre vermelho e vermelho - extremo que chegam ao solo em diferentes microhabitats na região de Tucuruí - PA

The present study was undertaken as a preliminary investigation of total irradiance between 300 and 1100 nm, as well as of the red/far red ratio of light reaching the soil of a tract of primary forest and of a clearing. The selected areas are located in th region near the town of Tucuruí, Para State, Brazil.Este trabalho visa preliminarmente estudar a irradiância total entre 300 e 1100 nm, assim como a razão vermelho-vermelho extremo que chegam ao solo de um trecho de floresta primária e de uma clareira. As áreas selecionadas estão localizadas numa região próxima a cidade de Tucurui, Estado do Pará, Brasil

Sensitivity studies on the photolysis rates calculation in Amazonian atmospheric chemistry ? Part I: The impact of the direct radiative effect of biomass burning aerosol particles

International audienceThe impact of the direct radiative effect of the aerosol particles on the calculation of the photolysis rates and consequently on the atmospheric chemistry in regional smoke clouds due to biomass burning over the Amazon basin is addressed in this work. It explores a case study for 19 September 2002 at LBA-RACCI-SMOCC (The Large-Scale Biosphere-Atmosphere experiment in Amazonia ? Radiation, Cloud, and Climate Interactions ? Smoke, Aerosols, Clouds, Rainfall and Climate) pasture site in SW Amazonia. The Tropospheric Ultraviolet Visible radiation model (TUV) version 4.2, (Madronich et al., 1987) is used for the photolysis rates calculation considering the layer aerosol optical depth from the Coupled Aerosol Tracer Transport model to the Brazilian Regional Atmospheric Modeling System (CATT-BRAMS) (Freitas et al., 2005). A dynamical aerosol model (Procópio et al., 2003) is included in the radiative transfer model to take into account the high temporal variability of the aerosol optical thickness. This methodology is tested by comparing modeled and measured clear sky solar irradiances. The results show a good agreement with measured PAR radiation values. The actinic flux attenuation, for AOT (500 nm) values around 1.94, decreases the photolysis rates by about 70% in the presence of near-ground smoke aerosol and above the smoke layer the photolysis process tends to increase by about 40%. A simulation of the ozone production is carried out using a one-dimensional photochemical box model and comparisons with observation are shown

Evaporação potencial de florestas.

A procedure adequated to the study of forest potencial evaporation is presented. Meteorological datas were obtained by automatic weather stations installed on the tower's top, at level 45 m, and constitute part of a large whole of information, which come being formed in the scope of Micrometeorological Experiment, at Ducke Reserve near from Manaus-AM. Observational period was August/83 - April/85, and stations provided houvly measurements of wind velocity, air temperature and specific humidity, solar and net radiation.", 'enUm procedimento para o estudo da evaporação potencial, horária de florestas é apre sentado. As informações meteorológicas analisadas, foram obtidas através de estações automáticas instaladas no topo de uma torre de 45 m, e fazem parte de um conjunto mais amplo de dados, que vem sendo formado no âmbito de um experimento de micrometeorologia se desenrola na Reserva Florestal Ducke nas proximidades de Manaus. As informações utilizadas cobrem o período de agosto de 1983 até abril de 1985 e são compostas por valores médios horários de velocidade do vento, temperatura e umidade especifica do ar, radiação solar e saldo de radiação

COUPLING NON-NEWTONIAN FLUID FLOW AND HEAT TRANSFER INSIDE A SCRAPED SURFACE HEAT EXCHANGER (SSHE)

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Avaliacao de fracoes retro-espalhadas a partir do truncamento de funcoes de fase.

The computation of backscattered fractions associated to very asymmetric phase functions (like those related to cloud droplets) is discussed. A large number of moments of the phase function is usually required for obtaining reliable backscattered fractions, mainly for low sun zenith angles. The truncation of the forward peak enables a dramatic reduction of that number, indicating that two-stream methods may be fairly improved without additional computational cost

DATA ACQUISITION FOR MODELING CONVECTIVE DRYING OF YACÓN (Smallanthus sonchifolius) SLICES

International audiencePoor in simple sugars and rich in fructo-oligosaccharides, yacón roots are considered as functional foods. However, their short shelf life demands a treatment prior to storage. This work aims to describe the convective drying of yacón slices and their properties, for posterior use in a numerical model to describe the process. Weight, diameter and height data were acquired for yacón slices dried in a specific convective dryer. Images obtained while drying show that samples underwent some browning, despite the blanching process prior to drying. Samples underwent some deformation and presented structural irregularities, apparently in random positions. Thermal properties obtained for the samples were similar to those of the literature, but soluble solids content was inferior. The absence of a constant rate period on the drying rate curve suggests that capillary diffusion and similar mechanisms control the drying rate along drying process

Observing ice clouds with a Doppler cloud radar

International audienceCloud systems containing ice particles ("ice clouds") must be realistically represented in numerical models devoted to weather forecasting and climate projection. Nevertheless, such clouds have not been fully characterized. The RadOn method (after Radar Only) has been developed for estimating microphysical properties of ice clouds from Doppler cloud radar observations. This method is here updated and applied to observations conducted in 2003-2004 with the Doppler cloud radar RASTA at the SIRTA observatory (Palaiseau, near Paris)

An overview of the ultraviolet index and the skin cancer cases in Brazil

This study relates regional and seasonal UV index (UVI) variations, number of skin cancer cases and population skin-color distribution in Brazil. UVI calculations were performed using the UV Global Atmospheric Model (UVGAME), whose characteristics and validations are provided in thiis article. Health and racial data sets are based on the health and census data collected by Brazilian governmental agencies in the past. The discussion covers cultural customs and details of health and educational campaigns in Brazil. Despite lower UV levels in the South and Southeast regions, the results show a number of nonmelanoma skin cancer (NMSC) cases regions, where the white population is predominant. In general, in the southern regions about 50 new NMSC cases per 100000 inhabitants have been diagnosed each year. These rates decrease almost 40% in the Central-North regions and more than 80% in Northeast region, where miscegenation is common. In addition, the UVI evaluation is extended to other South American sites with singular characteristics, e.g. populous cities located in high altitudes or those affected by the Antarctic ozone hole in the extreme south of the continent

Desempenho de modelos radiativos na avaliacao de irradiancias em presença de aerossol de queimadas

A inclusão de processos de interação entre a radiação solar e partículas de aerossol tem sido considerada como relevante no aperfeiçoamento dos modelos meteorológicos mais comumente utilizados para previsão de tempo e clima no mundo. Modelos meteorológicos empregados na previsão de condições ambientais na América do Sul são particularmente sensíveis a uma descrição realista da interação entre a radiação solar e o aerossol de queimadas. Este estudo compara observações de irradiância solar à superfície em presença de aerossol de queimadas e seus respectivos valores teóricos obtidos mediante diferentes modelos radiativos. As observações em questão foram efetuadas em setembro e outubro de 2002 nas proximidades de Ouro Preto dOeste (Rondônia), durante a realização do experimento RACCI/SMOCC. Alguns dos modelos radiativos em questão foram concebidos para emprego em modelos meteorológicos e portanto envolvem aproximações mais severas quanto à avaliação dos efeitos de espalhamento e de absorção de radiação solar por uma população de partículas em suspensão na atmosfera. Um segundo grupo de modelos radiativos considera representações mais sofisticadas com vistas à avaliação destes mesmos efeitos, além de permitir cálculos com maior resolução em comprimento de onda. Os resultados incluem testes de sensibilidade sobre a refletância da superfície, sobre a repartição vertical das partículas de aerossol, e sobre as propriedades ópticas do aerossol de queimadas

Coupling fluid flow, heat transfer and food product transformation in a tubular heat exchanger, including the influence of curved sections

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