Estimates of spectral wave attenuation in Antarctic sea ice, using
model/data inversion
Abstract
A model-data inversion is applied to an extensive observational dataset
collected in the Southern Ocean north of the Ross Sea during late autumn
to early winter, producing estimates of the frequency-dependent rate of
dissipation by sea ice. The modeling platform is WAVEWATCH IIIĀ® which
accounts for non-stationarity, advection, wave generation, and other
relevant processes. The resulting 9477 dissipation profiles are
co-located with other variables such as ice thickness to quantify
correlations which might be exploited in later studies to improve
predictions. An average of dissipation profiles from cases of thinner
ice near the ice edge is fitted to a simple binomial. The binomial shows
remarkable qualitative similarity to prior observation-based estimates
of dissipation, and the power dependence is consistent with at least
three theoretical models, one of which assumes that dissipation is
dominated by turbulence generated by shear at the ice-water interface.
Estimated dissipation is lower closer to the ice edge, where ice is
thinner, and waveheight is larger. The quantified correlation with ice
thickness may be exploited to develop new parametric predictions of
dissipation.