Oceanweather
has a long history of metocean studies for offshore Brazil beginning in 1999
with BOMOS and updated with BOMOSHU in 2010 and 2015. BOMOS-2 is the third
JIP (Joint Industry Project) expanding the previous JIPs’ grid domains from
just south of Natal, Brazil to the Uruguay border. This hindcast integrates the
background wind fields and boundary spectra from the ERA-5 (European Centre
for Medium-Range Weather Forecasts Reanalysis 5th Generation) dataset,
hand-drawn storm analyses, and a large body of metocean measurements to aid
in analysis and validation.
BOMOS-2
is a comprehensive study of the wind and wave climate offshore Brazil improving
upon the ERA-5 reanalysis. Statistical corrections were applied to the ERA-5
winds based upon comparisons of the ERA-5 winds to the QuikSCAT and WindSat
scatterometers. Corrections were applied to the most extreme winds as well
as mean corrections at the lower wind speeds. The hindcast incorporates an
expert wind field analysis of 137 storms using OWI’s proven kinematic
approach. Storms were selected to be analyzed based on insitu and remote-sensed
instruments as well as with a new peak clustering method.
Wave response
is modeled using the Wave Watch III (WW3) wave model on a nested grid system
(0.36 deg basin grid and 0.06 deg fine grid) and archived at a 30-minute time
step. The model is configured with spectral grids using 48 directional bins
and 31 frequency bands. The model also incorporates the effects of the
wave-current interaction using daily currents sourced from the NRL HYCOM
reanalysis from 1993 – 2012 and a daily climatology outside the available
period.
Proprietary
wind, wave, and spectra data obtained from the JIP participants allowed for
an extensive validation of the hindcast.
BOMOS-2 work
has been conducted in multiple phases. Phase 1
was completed in January 2020 for the continuous years 2000-2018. Phase 2
was finished in June 2021 extending the hindcast to 45 years, 1975-2019.
Also included are analyses of tropical cyclones Catarina (2004) and Iba
(2019).
