An Ocean Wind Doppler Model Based on the Generalized Curvature Ocean Surface Scattering Model: Fid-Bau Portal

An Ocean Wind Doppler Model Based on the Generalized Curvature Ocean Surface Scattering Model

Faozi Said

A Doppler centroid [Formula Omitted] model based on the generalized curvature ocean surface scattering model (generalized curvature model or GCM) is presented. Two key features are included in this model: a skewness-related phase coefficient based on empirical skewness coefficients of sea-surface-slope probability density function (pdf) for wind speed less than 10 m/s and effects from wave breaking for wind speed greater than 10 m/s. Simulated [Formula Omitted] values are exclusively compared with the empirical geophysical Doppler model function named CDOP, for [Formula Omitted] and [Formula Omitted] polarizations, various wind conditions, and incidence angles. Good agreement is found overall between CDOP and simulated [Formula Omitted] values. The overall bias for simulated [Formula Omitted] with and without skewness are 2.63 versus -0.51 Hz (14.6 versus -2.8 cm/s), respectively; overall standard deviations are 2.76 versus 3.53 Hz (15.3 versus 19.6 cm/s). For simulated [Formula Omitted], overall bias values with and without skewness are -0.16 versus -2.52 Hz (-0.9 versus -14 cm/s); standard deviations are 3.56 versus 4.32 Hz (19.7 versus 24 cm/s). The overall bias for simulated [Formula Omitted] with and without the wave breaking component are -0.08 versus 0.12 Hz (-0.4 versus 0.7 cm/s), respectively; corresponding standard deviations are 3.32 versus 4.75 Hz (18.4 versus 26.3 cm/s). Bias values for simulated [Formula Omitted] with and without the wave breaking component are -1.83 versus -2.02 Hz (-10.2 versus -11.2 cm/s), with corresponding overall standard deviations of 3.43 versus 4.87 Hz (19 versus 27 cm/s). The largest deviation from CDOP, of about 18 Hz (0.99 m/s), is found in the upwind direction for a 26° incidence angle, 10-m/s wind speed, and [Formula Omitted] polarization.