|Last update: Tuesday, 30-Sep-2008 16:11:54 CEST|
Estimation of short-wave directional distribution from HF radars: Comparison with model predictions
byYukiharu Hisaki (University of the Ryukyus)
The radar-estimated directional distributions of Bragg wavelength are estimated from the ratio of observed first-order scattering. These short-wave directional distributions are estimated for the 2-parameter model and 4-parameter model. The short-wave directional distributions are compared with model predictions from the wave energy balance equation and the agreement is good. The parameterization of the source function in the energy balance equation is investigated.
In particular, the effect of the nonlinear source function on the prediction of short-wave directional distributions is investigated. The nonlinear source function is calculated from both the exact computation and the Discrete Interaction Approximation (DIA).
The agreement between radar-estimated short-wave directional distributions and model predictions is good. The 4-parameter model is better than the 2-parameter model to estimate short-wave directional distribution from HF ocean radar. The short-wave direction change associated with a sudden wind shift can be reproduced both from the exact computation and the DIA. The short-wave directional distributions calculated from the exact computation are narrower than those calculated from the DIA and estimated from the HF radar.