Medium Resolution Microwave, Thermal and Optical Satellite Sensors: Characterizing Coastal Environments Through the Observation of Dynamical Processes

Abstract

Synthetic Aperture Radar (SAR) satellite sensors can provide relevant information about a variety of features related to dynamical processes. Due to the high resolution of available SAR sensors, it is possible to detect details of circulation and small-scale processes which are not observable by other satellite sensors frequently used for ocean research, including the Advanced Very High Resolution Radiometer (AVHRR) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Additionally LANDSAT-Thematic Mapper (TM)/ Enhanced Thematic Mapper Plus (ETM+) thermal and optical channels can be used to observe sea surface temperatures and surface layer ocean color (upwelled radiance), as well as sun glint patterns of surface roughness (reflected radiance) at a high spatial resolution, comparable to that of SAR. A large amount of LANDSAT TM/ETM+ and ERS-SAR data were processed to observe in detail some dynamical phenomena in the coastal environment of the Southwestern Atlantic Ocean, including fronts, internal waves, eddies, upwelling and bathymetric signatures. The purpose of this chapter is to present and discuss examples of these phenomena observed in three dissimilar sectors located along a broad range of latitudes (from 33 degrees S to 54 degrees S). Results indicate that, independently of the study area, medium resolution optical, thermal, and microwave sensors can provide relevant information about the properties of coastal environments by the observation of ocean dynamic processes. In addition, this study demonstrates that each sensor can capture different aspects or properties of the same process. Collectively, all this information provides a better understanding of the characteristics of coastal waters, highlighting their influence on marine biodiversity.