A comparative assessment on the use of SAR and high-resolution optical images in ocean dynamics studies

Abstract

A comparison of Synthetic Aperture Radar (SAR) images acquired by the ERS-2 and RADARSAT-1 satellites with Landsat Thematic Mapper (TM) images acquired close in time is presented. Similarities and differences on the kind of ocean information they provide are discussed. The images were acquired over the Brazil–Malvinas (Falkland) Confluence under different solar elevation and azimuth angles. Ocean features observed by both types of sensors are discussed. These observations show that (1) at high solar angles, sun glint prevails over upwelled water-leaving radiance resulting in optical images that tend to provide dynamical information similar to that obtained from SAR imagery and (2) at low solar zenith and azimuth angles, upwelled radiation tends to prevail over sun glint, providing typical ocean colour and water quality information that can still complement and aid in the interpretation of SAR observations.

Acknowledgments

The authors are grateful to the Argentine Comisión Nacional de Actividades Espaciales for providing the Landsat-5 TM and ERS-2 SAR data and to the Canadian Center for Remote Sensing for providing the RADARSAT-1 data.

Notes

An updated version of a paper originally presented at Oceans from Space ‘Venice 2000’ Symposium, Venice, Italy, 9–13 October 2000.