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SODA4: A Mesoscale Ocean-Sea Ice Reanalysis
  • James A. Carton,
  • Gennady A. Chepurin
James A. Carton
University of Maryland, College Park

Corresponding Author:[email protected]

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Gennady A. Chepurin
University of Maryland, College Park
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This paper introduces the new eddy-resolving global Simple Ocean Data Assimilation version 4 (SODA4) ocean/sea ice reanalysis. As with its predecessor SODA3, sequential data assimilation is used to constrain the evolving temperature and salinity fields using World Ocean Database profiles, in-situ and satellite sea surface temperature observations, and sea ice thickness estimates as constraints. The numerical model is based on NOAA/Geophysical Fluid Dynamics Laboratory MOM5.1/SIS1 numerics with nominal l/10° horizontal resolution, and 75 levels in the vertical. Surface forcing is provided by a bias-corrected version of the European Center for Medium Range Weather Forecasts ERA5 forcing, while continental discharge is provided by a separate monthly observation-based discharge dataset. A 13-year (2010-2022) reanalysis experiment (SODA4.15.2) is compared to the coarser resolution, but otherwise similar SODA3.15.2 and to assimilated and independent observations. These comparisons show that the greatest reduction in time mean bias occurs near strong fronts, which become narrower and stronger. Eddy variability is increased, increasing eddy heat transport. Improved vertical resolution produces shallow summer temperature and salinity stratification which is most noticeable in midlatitudes and the eastern tropical Pacific and Atlantic in Northern Hemisphere winter.
30 Sep 2023Submitted to ESS Open Archive
02 Oct 2023Published in ESS Open Archive