On consistent parameterizations for both dominant wind-waves and
spectral tail directionality
Abstract
Numerical wave models have been developed to reproduce the evolution of
waves generated in all directions and over a wide range of wavelengths.
The amount of wave energy in the different directions and wavelength is
the result of a number of physical processes that are not well
understood and that may not be represented in parameterizations. Models
have generally been tuned to reproduce dominant wave properties:
significant wave height, mean direction, dominant wavelengths. A recent
update in wave dissipation parameterizations has shown that it can
produce realistic energy levels and directional distribution for shorter
waves too. Here we show that this new formulation of the wave energy
sink can reproduce the variability of measured infrasound power below a
frequency of 2 Hz, associated with a large energy level of waves
propagating perpendicular to the wind, for waves with frequencies up to
at least 1 Hz. The details are sensitive to the balance between the
non-linear transfer of energy away from the wind direction, and the
influence of dominant and relatively long waves on the dissipation of
shorter waves in other directions.