Distribuição da temperatura da superfície do mar e dos sedimentos suspensos na plataforma continental capixaba utilizando imagens landsat5/TM

• Autor(a) principal: Teixeira, Gregório Luiz Galvão
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/10275
• topic: Engenharia Sanitária; Sensoriamento remoto; Landsat (satélites); Plataforma continental; 628

Monitoring water quality in the inner Continental Shelf (CS) has shown to be costly when conventional methods are employed. Orbital Remote Sensing appears as an alternative tool to monitoring important variables such as sea surface temperature (SST) and suspended sediment concentration (SSC). This study aims at assessing spatial distribution of SST and SSC in the continental shelf area of the Brazilian State of Espírito Santo using, respectively, Band 2 (0.569µm) and Band 6 (11.435µm) data from Thematic Mapper (TM) sensor on board of satellite Landsat 5. Thus, a data bank was built out of 127 images pre-processed and registered by the TM sensor. Of these 127 images, only 4 were selected for SST and SSC analyses. During image pre-processing, geometric and reflectance corrections are made. Geometric correction is carried out based on a second image orthorectified so that there is correct georeferencing. Reflectance correction is performed using an atmospheric compensation model. Through this model, sea surface reflectance is obtained. SST is estimated based on the adjustment of Brightness Temperature (BT) derived from Band 6 with data from the Multi-scale Ultra-high Resolution Sea Surface Temperature (MURSST). In case of not enough sediment field data to carry out curve adjustment, SSC calculation is performed using the empirical logarithm algorithm proposed by Tassan (1987), which uses Band 2 data. The corrected reflectance spectrum is compared to TOA reflectance spectrum. The corrected spectrum complied with the literature on natural targets analyzed: cloud, vegetation, water and water with sediments. Landsat BT adjustment with SST of MURSST showed to be significant, according to statistical F-test and to r 2 = 0.87. Results of the 4 scenes for SST and SSC fields. For winter SST, a more homogeneous temperature of ∼23◦C is observed, whereas the summer scene is characterized by thermal contrasts between the area closer to the coast (∼21◦C) and the area further from the coast (∼26◦C). Further, hotspot plumes associated to the mouths of Jucu and Doce Rivers and Espírito Santo Bay are also verified. For the SSC fields, higher-concentration plumes are observed, which are advected southeast. The highest concentrations are associated to the Doce River (over 60 mg/L). SSC values comply with the values reported in the relevant literature, i.e. close to the coastal line, in the summer scene, values of ∼15mg/L were verified. On the other hand, for autumn and winter scenes, these values are about ∼35mg/L. Both atmospheric correction and SSC distribution values found in this study are according to the data and studies reported in the relevant literature. Therefore, we can conclude that the method employed showed to be functional to process the data gathered in this study.