Navegando por Autor "Lorenzzetti, João Antonio"

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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
(2010-11) Poças, Jansen Santos; Lorenzzetti, João Antonio; Melo Filho, Eloi; Franco, Davide
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.
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Multi-sensor satellite and in situ measurements of a warm core ocean eddy south of the Brazil–Malvinas Confluence region
(2006) Souza, Ronald Buss de; Mata, Mauricio Magalhães; Garcia, Carlos Alberto Eiras; Kampel, Milton; Oliveira, Eduardo Negri de; Lorenzzetti, João Antonio
A warm core eddy was detected south of the Brazil–Malvinas (Falkland) Confluence (BMC) region in satellite images of the southwestern Atlantic Ocean in late 2002. The structure was also sampled by in situ instruments deployed by a ship in 2 days of November 2002. An analysis of satellite data was performed to account for the lifecycle, dimension, surface temperature, surface chlorophyll concentration, surface height anomaly and displacement of the eddy since it was detached from the Brazil Current in September 2002. Satellite data were derived from several sources such as the AMSR-E, MODIS and radar altimeter. The structure lasted 64 days at south of th Brazil–Malvinas Confluence region later being re-assimilated by the Brazil Current return flow. In situ data collected during 2 days showed that the eddy was about 150m deep, 5.5-C warmer and 1 practical salinity unit saltier than adjacent waters. The salt anomaly associated to the eddy was estimated as 1.37 1012kg while its heat content was 4.24 1018 J. These are typical estimates for eddies present at the BMC region. Sea surface temperature (SST), chlorophyll concentration, and sea surface height anomaly time series were analyzed for the eddy’s center along its trajectory path throughout its lifetime. Mean translational velocities for the eddy during its lifetime were computed from visual interpretation and by using an adaptation of the Maximum Cross-Correlation (MCC) method on AMSR-E SST images. The overall deviation between the two methods was 26%.This suggests that the MCC method has a potential to be applied in monitoring programs to automatically account for the translational velocities of eddies in the BMC region.
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Resposta morfológica da foz do Rio São Francisco, devido à retenção de sedimentos nos reservatórios.
(2013) Bandeira, Jefferson Vianna; Farias, Eduardo Guilherme Gentil de; Lorenzzetti, João Antonio; Salim, Lécio Hannas
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.