Estimation of Breaking Wave Height from Ultrawideband Radar Data
Abstract
We describe a multipath model for the microwave backscatter produced by breaking water waves that promises to provide a means to estimate breaker height when applied to ultrawideband (UWB) radar data. Particularly at low grazing angles, multipath scattering between the wave crest and the front face of the breaker is known to play an important role in the scattering mechanism. From a ray tracing perspective, the scattering can follow a direct path from the radar to the crest and back again, or its path can involve a bounce off the front face. Interference between components that follow these different paths produces peaks and nulls when the backscatter data is viewed in the RF frequency domain, with the peak spacing dependent upon the grazing angle and the breaker height. The simple model described in this report provides the analysis required to estimate the breaker height from the location of the peaks. The model indicates that very low grazing angles less than 5 degrees are preferable, as the peak spacing is then wide enough to measure with modest frequency resolution while the distinctive polarization response of the front-face reflection coefficient also provides a means to reject signals that are not generated by the assumed multipath mechanism.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 29, 2023
- Accession Number
- AD1212317
Entities
People
- Mark A. Sletten
Organizations
- United States Naval Research Laboratory