Radar altimetry: Introduction and application to air-sea interaction

Abstract

Radar altimeters are among the more common satellite-borne Earth Observation instruments with a long history including continuous data since 1991. They are also exceptionally versatile providing information on sea level, ocean dynamics, wind speed and a number of wave parameters. Radar altimetry is a "point" rather than a "swath" instrument so that sampling resolution by a single altimeter is relatively poor in both space and time. Also the sizeable footprint restricts use of altimetry to greater than 10 km from any coast, with some restrictions at a greater distance. The sampling limitations do not negate the usefulness of altimetry, either in isolation or in combination with other instruments or modelling. Climatologies of sea level and wave parameters built from altimetry provide a unique perspective on both a regional and global scale. Measurements of individual storm events provide a test for both wave and storm-surge modelling and could be useful in Near Real Time applications. New interpretations of satellite altimeter waveforms and dual-frequency data, and new advanced altimeter concepts, continuously present new products to broaden the geophysical applications of radar altimetry. © 2008 Springer Science+Business Media B.V.