A global wave parameter database for geophysical applications. Part 3:
improved forcing and spectral resolution
Abstract
Numerical wave models are used for a wide range of applications, from
the global ocean to coastal scales. Here we report on significant
improvements compared to the previous hindcast by Rascle and Ardhuin
(2013). This result was obtained by updating forcing fields, adjusting
the spectral discretization and retuning wind wave growth and swell
dissipation parameters. Most of the performance analysis is done using
significant wave heights (Hs) from the recent re-calibrated and denoised
satellite altimeter data set provided by the European Space Agency
Climate Change Initiative (ESA-CCI), with additional verification using
spectral buoy data. We find that, for the year 2011, using wind fields
from the recent ERA5 reanalysis provides lower scatter against satellite
H s data compared to historical ECMWF operational analyses, but still
yields a low bias on wave heights that can be mitigated by re-scaling
wind speeds larger than 20 m/s. Alternative blended wind products can
provide more accurate forcing in some regions, but were not retained
because of larger errors elsewhere. We use the shape of the probability
density function of H s around 2 m to fine tune the swell dissipation
parameterization. The updated model hindcast appears to be generally
more accurate than the previous version, and can be more accurate than
the ERA5 H s estimates, in particular in strong current regions and for
Hs greater than 7 m.