Water Wave Slope Estimation.
SYSTEMS CONTROL TECHNOLOGY INC PALO ALTO CA
Pagination or Media Count:
The statistical description of the geometrical features of the ocean surface such as the elevation and the slope is needed in many diverse areas of application and has been the goal of many investigations. Aside from the basic interest of physical oceanographers, the interest in these features has been stimulated by the need for remote sensing of large areas of the ocean from satellites with various sensors including synthetic aperture radar. Understanding of electromagnetic scattering by the ocean surface is necessary for this purpose. While theories abound, one of the most elusive ingredients in a complete understanding of the problem, has been the geometry of the surface, as given by the spatial distribution of the slopes over a sizeable area of the ocean surface. Typically, experimental measurements have been of two kinds a statistical results representatives of a large area and b a time series of measurements at a point. Except for the work on stereo observations of waves, no measurements of the instantaneous surface geometry over a two-dimensional area have been reported. Our own interest arose during a detailed analysis of the ability of the Stilwell method to measure the directional power spectra of ocean waves. Under certain conditions of observation geometry and illumination conditions, an optical image of the ocean surface can be interpreted to obtain a good approximation of the local surface slope components along the look azimuth.
- Physical and Dynamic Oceanography