Ocean state measurement method using radar

Method for Calculating X-Band Radar Backscatter Coefficients Based on Ocean Spectra Reflecting Water Depth and Sea State

This technology is an ocean state measurement method that calculates sea surface radar backscatter coefficients by generating an ocean spectrum that accounts for wind speed, significant wave height, water depth, and long/short wave components, then combining it with Bragg microwave wavenumbers. It also incorporates a Vector Radiative Transfer (VRT) model to address foam particle scattering, as well as surface asymmetry and shadowing effects.

While X-band marine radar is widely used for sea state observation, it has been difficult to accurately predict wave parameters and backscatter because wave systems vary based on water depth, fetch, wave breaking, refraction, and local currents, rather than just wind speed. In particular, there has been a lack of calculation models that simultaneously reflect nearshore wave parameters and short wind-wave spectra.

This technology predicts wave parameters and ocean spectra for specific sea areas using empirical formulas that include inverse wave age functions and curvature spectra, allowing for the theoretical and practical calculation of backscatter coefficients for both vertical and horizontal polarization. It can be applied to navigation support radar, marine remote sensing, and sea state monitoring for coastal structure design, enabling more reliable estimation of wave height and sea surface conditions using only radar imagery.

‍

‍

Key Features:

• Step of calculating an ocean spectrum that reflects the omnidirectional spectrum, spreading function, depth function, wind speed, significant wave height, and long/short wave components
• Step of calculating the backscatter coefficient using the ocean spectrum and the Bragg microwave wavenumber defined by the radar incidence angle and wavelength
• Backscatter model that calculates scattering from foam-free sea surfaces by including surface asymmetry functions, modified curvature coefficients, shadowing functions, and polarization-specific coefficients
• Method for calculating backscatter coefficients valid in deep-sea regions using a VRT model that reflects the scattering and absorption coefficients of foam particles and Fresnel reflection coefficients

‍