O sensoriamento remoto aplicado na estimativa da concentração de clorofila no mar

<abstract language="eng">In this paper the feasibility of estimating the chlorophyll content of ocean waters through the use of multispectral remote sensors on board of orbiting satellites, is discussed. Some aspects of the physical foundations of the interaction processes of visible light (380-770 nm) with the atmosphere and liquid mass and some models for this detection, are also discussed

Detecção de alvos oceânicos por meio de imagens SAR

Digital image processing methods are applied to RADARSAT SAR images collected for the Brazilian SE continental shelf region for target detection purposes. Environmental in situ data, such as surface wind, sea surface temperature, sea state, ship size, orientation, position, speed etc, were collected by the Brazilian Navy to help the analysis and interpretation of scenes.Pages: 847-84

Análise comparativa dos espectros de ondas observados ao largo de Santa Catarina e de Rio Grande por ondógrafos, radar de abertura sintética e derivados de modelo

Radares de Abertura Sintética (SAR) a bordo de satélites constituem uma importante ferramenta para o monitoramento do campo de ondas na superfície do oceano. Entretanto, a geração do espectro bidimensional dessas feições oceânicas por meio de SAR possui limitações associadas ao mecanismo de imageamento (processamento Doppler) e ao movimento orbital das partículas d’água. A fim de avaliar quão severas são essas restrições para as regiões ao largo da costa da Ilha de Santa Catarina/SC e de Rio Grande/RS, este trabalho se propõe a realizar comparações dos espectros direcionais de onda, derivados de imagens do radar presente no satélite Envisat, com dados provenientes do modelo de previsão de ondas WW3 e de ondógrafos.Synthetic Aperture Radar on board satellites is an important tool for the monitoring of ocean surface wave fields. However, the generation of the satellite twodimensional wave spectrum presents limitations associated to the sensor imaging mechanism (Doppler processing) and the wave orbital motion. In order to evaluate how severe are such restrictions for the Santa Catarina Island/SC and Rio Grande/RS coasts, we present in this paper some comparisons of the directional wave spectra from Envisat radar images, against wave model WW3 data and buoy measurements

Resposta morfológica da foz do Rio São Francisco, devido à retenção de sedimentos nos reservatórios.

Usando uma coleção de imagens de satélites obtida desde a década de 1980, mapas antigos e fotos aéreas, o trabalho descreve as mudanças morfológicas na foz do Rio São Francisco, nordeste do Brasil, causada pela retenção de sedimentos devido às diversas barragens construídas na sua bacia hidrográfica desde 1955. Apresentam-se resultados semi-quantitativos da regressão da linha de costa e a variação temporal de seu alinhamento, considerando a interface entre a vegetação e a areia como referência do processo erosivo.Using a collection of satellite images obtained since the 1980 decade, historical maps and aerial photos, this paper describes morphological changes at the mouth of São Francisco River, north-eastearn Brazil, caused by retention of sediments due to the various dams constructed in its hydrographic basin since 1955. Semi-quantitative results of the regression of the coastline and the temporal variation of its alignment, considering the interface of the vegetation and the sand as reference of the erosive process, are presented

Integrating historical topographic maps and SRTM data to derive the bathymetry of a tropical reservoir

This paper proposes a fast and inexpensive method for estimating the bathymetry of hydroelectric reservoirs. Brazil has more than 30 large hydroelectric reservoirs with a combined volume exceeding one billion cubic meters. The hydroelectric sector is responsible for 97% of the energy production in Brazil and is the largest hydroelectric park in the world. Among the variables affecting the environmental impacts of reservoirs, depth plays a major role because it influences the aquatic system hydrodynamics. Reservoir depth distribution (i.e., the bathymetry) is also a fundamental factor controlling the physicalchemical and biological properties of the system. However, the acquisition of bathymetric information for the large reservoirs in Brazil is not a simple task because: (1) most of the topographic maps available in the area of the lake have a very small scale (1:100,000 and smaller), (2) larger charts are the property of the hydropower companies and are classified, and (3) the size of the reservoirs prevent the use of bathymetric surveys. The proposed method of integrating historical and Shuttle Radar Topography Mission (SRTM) topographic data allowed for the estimation of the bathymetry of the Itumbiara reservoir with R2 = 0.98 (n = 100, &#961; = 0.00) and RMSE = 3.78 m. For researchers who need a rapid and simple method to develop bathymetric maps of hydroelectric reservoirs, the proposed method can provide a simple and fast alternative to more data intensive methods.Pages: 311-31