X band microwave backscattering from ocean waves
- TRW Space and Electronics, Redondo Beach, CA (United States)
Backscattering experiments at microwave frequencies were conducted off the west coast of Scotland in the summer of 1991. Using a dual-polarization, eight-frequency, X band, coherent scatterometer mounted on the bow of a boat, the authors measured time-resolved backscattering from ocean waves at a range of grazing angles from 10{degrees} to 70{degrees}. From the grazing-angle-dependent signals and their Doppler spectra, the authors are able to differentiate Bragg scattering from non-Bragg scattering and resolve {open_quotes}peak separation{close_quotes} between the vertical and horizontal polarizations. The authors observe instances of {open_quotes}super{close_quotes} events, i.e., instances when the horizontal polarization return power equals or exceeds the vertical polarization power at particular frequencies. They find that {open_quotes}super{close_quotes} events occur not only at low gazing angles, lifetime-dominated, non-Bragg scattering contributes noticeably to returns of both polarizations, but is dominant in providing returns for the horizontal polarization. They examine {open_quotes}spiking{close_quotes} events and find that they can be related to, but need not be limited to, breaking wave events. By comparing the data of upwind runs with cross-wind and circle runs, the authors obtain wind direction dependence of Doppler spectra, which further assists in the identification of scattering mechanisms. 42 refs., 218 figs., 2 tabs.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 183273
- Journal Information:
- Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: C2 Vol. 100; ISSN JGREA2; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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