Radar backscatter from the sea controlled experiments
Abstract
This is the final report on ONR Grant N00014-89-J-3022. Since most of the work was in journal articles, conference proceedings, and reports, this report is brief. Work continued, and was largely concluded, on analysis of the TOWARD, SAXON-CLT, and NILDEX data sets. Comparison between optical and radio measurements of ripple spectra at TOWARD showed favorable results. Although the wind direction was usually unfavorable for SAXON-CLT, useful data was obtained on modulation in the crosswind direction. It was also demonstated that a vector slope gauge can work, but for logistic reasons its deployment made its footprint close to the tower. Hence, the data are useful only for proof of concept, not for oceanographic application. A new theory of SAR imaging of the ocean was developed. It incorporates elements of previous theories, but shows an improved way to find out the effects of signal modulations on the observed spectra. It confirms, by a different method, the results from several other theoretical and experimental studies on processor focus adjustment. These show optimum image contrast occurs for along-track wave motion when the processor is set to (phase velocity)/2. The method of analysis used allowed closer examination of the basis for the two-scale (Bragg resonance with slope modulation) model for ocean backscatter. The results cast some doubt on the validity of the Bragg-scatter model for explaining many observed phenomena.
- Publication:
-
Final Report Kansas Univ. Center for Research
- Pub Date:
- November 1990
- Bibcode:
- 1990kans.rept.....M
- Keywords:
-
- Backscattering;
- Bragg Angle;
- Data Base Management Systems;
- Image Contrast;
- Oceanography;
- Oceans;
- Optical Properties;
- Optimal Control;
- Environmental Tests;
- Marine Environments;
- Measuring Instruments;
- Phase Velocity;
- Radar Echoes;
- Radiometers;
- Resonance;
- Ripples;
- Spectral Theory;
- Vector Analysis;
- Velocity Measurement;
- Velocity Modulation;
- Wind (Meteorology);
- Wind Direction;
- Communications and Radar