A microwave technique to improve the measurement of directional ocean wave spectra

Measurement of ocean surface slopes and wave spectra using polarimetric SAR image data

“…This orientation angle modulation will be present in images produced by either a SAR, or a RAR. Either (1) this orientation angle modulation, or, (2) a related polarimetric intensity modulation (Schuler & Lee, 1995) may then be used to make wave measurements in the azimuth direction. By either method, the measurement gap in the azimuth direction is then filled.…”

Comparison of polarimetric SAR techniques for the measurement of directional ocean wave spectra

“…Figure 2 This polarization intensity modulation acts as a separate source-term for the overall microwave modulation transfer function. This technique, introduced by Schuler et al [2,4] shows potential for making measurements on azimuthallytraveling ocean waves. Important to the success of this technique is the fact that ocean polarization signatures are 1) relatively constant in morphology, and 2) have regions with large intensity variations related to perturbations in the orientation.…”

“…The optimal orientation occurs at the point where the second derivative of the radar cross-section is equal to zero. This position of maximum sensitivity to azimuthal wave tilts o ψ will vary as a function of the polarization ratio ρ Studies using a RAR imaging model [2] indicate that undesirable effects such as spectral-splitting and distortion of the radar-image spectrum may be greatly reduced for the case of azimuthally traveling waves. Splitting of the spectrum parallel to the azimuthal direction can be almost eliminated [2].…”

“…This position of maximum sensitivity to azimuthal wave tilts o ψ will vary as a function of the polarization ratio ρ Studies using a RAR imaging model [2] indicate that undesirable effects such as spectral-splitting and distortion of the radar-image spectrum may be greatly reduced for the case of azimuthally traveling waves. Splitting of the spectrum parallel to the azimuthal direction can be almost eliminated [2]. This model allows comparisons to be made between conventional RAR spectra, and spectra developed with the polarization modulation term included.…”

“…These methods utilize 1) SAR intensity modulations measured at linear-basis polarizations [2] and 2) orientation/alpha angle modulations [3]. The alpha angle is from the Cloude-Pottier decomposition [6].…”