Ocean wave spectral distortion in airborne synthetic aperture radar imagery during the Norwegian Continental Shelf Experiment of 1988
| Autor: | Clifford L. Rufenach, Johnny A. Johannessen, Norman P. Malinas, Robert A. Shuchman |
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| Rok vydání: | 1991 |
| Předmět: |
Atmospheric Science
Spectral shape analysis Ecology C band Paleontology Soil Science Forestry Aquatic Science Oceanography Swell Wind speed Azimuth Wavelength Geophysics Space and Planetary Science Geochemistry and Petrology Distortion Wind wave Earth and Planetary Sciences (miscellaneous) Physics::Atmospheric and Oceanic Physics Geology Earth-Surface Processes Water Science and Technology Remote sensing |
| Zdroj: | Journal of Geophysical Research. 96:10453 |
| ISSN: | 0148-0227 |
| DOI: | 10.1029/91jc00418 |
| Popis: | C band radar images of ocean gravity waves off the Norwegian coast were processed into one-dimensional azimuth spectra. These spectra were used to measure the azimuth spectral (width) cutoff on the basis of a least squares fit to a Gaussian spectral shape. The widths were calculated for a range of wave heights (2–5 m) and wind speeds (2–18 m/s) during 3 days in March, 1988. Velocity smearing (συ) estimates were extracted, independent of R/V and incidence angle, based on an imaging model and the measured azimuth cutoffs with συ values varying from 0.4 to 0.7 m/s. Quantitative velocity smearing estimates are important as input to models describing the distortion in wave imagery. We propose a first-order model which neglects velocity bunching for ocean swell with peak wavelengths longer than about 250 m. This model is offered as a first estimate of when ocean wave swell will be detected by the C band SAR on board the ERS 1 spacecraft. The model predicts that this swell will be imaged under light winds of the order of 2–4 m/s. Higher wind speeds cause larger smearing, which may result in significant distortion of the imaged swell provided that the swell is traveling near the direction of the spacecraft ground track. |
| Databáze: | OpenAIRE |
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