Remote sensing by radar altimetry

The satellite radar altimeter was found to be a versatile and powerful tool for the remote sensing of the oceans. Thus, data from the Geos-C and Seasat-1 altimeters have supported research in geodesy, bathymetry, mesoscale oceanography, tides, ice topography, winds and waves. The radar altimeter is a conceptually simple instrument, which employs a short-pulse radar that measures the distance between the satellite orbit and the subsatellite point on the ocean's surface with the precision of a few centimeters. The Geosat-A altimeter will produce the dense data set required for geodesy. Future altimeters will incorporate redundancy for long life and dual-frequency operation to remove ionospheric effects. It is pointed out that the multibeam altimeter under development will provide the spatial and temporal sampling required for the remote sensing of mesoscale oceanography.