Uso de parâmetros “All-pixel-SST” na estimativa de campos de TSM com base em dados do sensor AVHRR Eduardo da Silva Gigliotti 1 Luiz Eduardo de Souza Moraes 1 Ronald Buss de Souza 1 Olga Tiemi Sato 2 1 Instituto Nacional de Pesquisas Espaciais - INPE Caixa Postal 515 - 12245-970 - São José dos Campos - SP, Brasil {edsilva,lemoraes,ronald}@dsr.inpe.br 2 Instituto Oceanográfico da Universidade de São Paulo – IOUSP Caixa Postal 05.508-120 - São Paulo – SP, Brasil olga@io.usp.br Abstract. This paper proposes an alternative method to improve sea surface temperature plots (SST), using data distributed as all-pixel-SST product from the Pathfinder v.5 Project. The National Oceanic and Atmospheric Administration NOAA/NASA Oceans Pathfinder Sea Surface Temperature data are derived from measurements made by the Advanced Very High Resolution Radiometers (AVHRRs) on board the NOAA polar orbiting satellites. The Pathfinder algorithm are based on the NOAA/National Environmental Satellite Data and Information Service nonlinear SST operational algorithm (NLSST) which applies decision trees to determine objectively pixel cloud contamination and quality level. The method uses a temporal interpolation in order to eliminate data contamination by the presence of clouds. After substitution of all contaminated pixels, SST maps from the resulting data set, and from the Best Sea Surface (BSST) product, also available in the Pathfinder Project, were visually compared. Additionally, variability decomposition in Empirical Orthogonal Functions (EOF) of both data sets was performed by Principal Component Analysis (PCA). The efficiency of our temporal interpolation method was verified by determining the correlation coefficients between the spurious and processed data. SST fields derived from all-pixel interpolated data allowed the detection of important oceanic features, such as upwelling fronts and eddies, which were not observed in BSST fields. On the other hand, variability of the all-pixel time series on the first three EOF modes was lower than on BSST time-series. Analysis of the correlation coefficient maps showed a good correlation with the original data, despite the interpolation procedure. Palavras-chave: Southeastern Brazilian Bight, sea surfece temperature, Plataforma Sudeste Brasileira, temperatura da superfície do mar, AVHRR. 1. Introdução O estudo da dinâmica de processos oceânicos com base nos campos de temperatura da superfície do mar (TSM) é severamente limitado por fenômenos meteorológicos que modificam as propriedades atmosféricas e controlam as concentrações de vapor d’água, CO 2 e aerossóis. A presença de nuvens, em especial, inviabiliza medidas locais adequadas da radiância do infravermelho termal, o que resulta na contaminação destes campos por valores irreais de TSM. O sensor Advanced Very High Resolution Radiometer (AVHRR) é o radiômetro multiespectral a bordo dos satélites da série TIROS-N da National Oceanic and Atmospheric Administration (NOAA), amplamente utilizado na geração de estimativas de TSM. O AVHRR apresenta cinco canais espectrais, dos quais três abrangem a faixa do infravermelho termal (1.58-12.5μm). Atualmente, a NOAA emprega o algoritmo NLSST (Non Linear Sea Surface Temperature) na correção do efeito dos constituintes atmosféricos (Kilpatrick et al, 2001). Esse algoritmo é uma variante da técnica MCSST (Multi-Channel Sea Surface Temperature), que se baseia em operações de regressão multipla entre pares diferentes de combinações de 2 ou 3 canais do sensor AVHRR, resultando em sistemas de equações de correção atmosférica 6479