Title :
Electromagnetic bias in sea surface range measurements at frequencies of the TOPEX/Poseidon satellite
Author :
Hevizi, Laszlo G. ; Walsh, E.J. ; McIntosh, Robert E. ; Vandemark, Douglas ; Hines, Donald E. ; Swift, Robert N. ; Scott, John F.
Author_Institution :
Dept. of Electr. & Comput. Eng., Massachusetts Univ., Amherst, MA, USA
fDate :
3/1/1993 12:00:00 AM
Abstract :
Range measurements made by satellite radar altimeters experience an electromagnetic (EM) bias toward the troughs of ocean waves. Measurements taken with the NASA altimeter on the TOPEX/Poseidon satellite in a series of aircraft flights during the Surface Wave Dynamics Experiment (SWADE) indicate that EM bias is slightly higher at 5.3 GHz than at 13.6 GHz, and that the magnitudes of both biases increase with increasing wind speed, as does their difference. Tower, airborne, and satellite measurements show a consistency in the characteristics of the wind speed dependence but suggest that bias decreases with increasing altitude. The airborne measurements appear to be the most reasonable basis for correcting the NASA altimeter range data from the TOPEX/POSEIDON satellite. A preliminary analysis of data acquired at 20.3 m/s in the Southern Ocean Waves Experiment (SOWEX) has given confidence that the quadratic models for the prelaunch EM bias corrections are more appropriate for wind speed dependence than linear models
Keywords :
height measurement; ocean waves; oceanographic techniques; remote sensing by radar; wind; 13.6 GHz; 5.3 GHz; SHF; SWADE; Surface Wave Dynamics Experiment; TOPEX/Poseidon satellite; ocean waves; quadratic models; remote sensing; satellite radar altimeters; sea surface range measurements; troughs; wind speed; Electromagnetic measurements; NASA; Ocean waves; Radar measurements; Satellites; Sea measurements; Sea surface; Spaceborne radar; Velocity measurement; Wind speed;
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on