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SODA: A Reanalysis of Ocean Climate


SODA3.3 Description

Model
Similar to those implemented as part of the Geophysical Fluid Dynamics (GFDL) CM2.5 coupled earth system model (Delworth et al., 2012). Ocean numerics: GFDL MOM5 with a third-order finite volume advection scheme. The numerical grid has roughly isotropic horizontal grid cells with dimensions varying from 28 km at the equator to 8-11 km at high latitude. In the Arctic the grid shifts to two geographically displaced north poles. Horizontal mixing consists of the Fox-Kemper et al. (2011) parameterization for the effects of submesoscale mixed layer eddies, and Smagorinsky biharmonic viscosity and a prescribed background viscosity that is enhanced next to western boundaries (Griffies and Hallberg 2000). Vertical mixing uses the K-profile parameterization scheme of Large et al. (1994) and the coastal tide mixing scheme of Lee et al. (2006). Sea ice is simulated by the three layer (one snow and two ice) GFDL Sea Ice Simulator (SIS) for which the ice thickness in each layer is divided into five categories. The model equations include the viscoelastic mechanics of Hunke and Dukowicz (1997) and thermodynamics of Winton (2000). The parameterization of Martin and Adcroft (2010) is included to simulate the effects of icebergs.

Method
Sequential deterministic estimation and a 10-dy update cycle. Bias correction is currently not implemented. The error covariances have undergone some revision since SODA2.1 and the updating now extends to 2 km depth.

Data
World Ocean Database 2013 with updates as of late-2015 (Boyer, et al., 2013) using bias corrections for the bathythermograph records as proposed by Levitus et al. (2009)

Forcing
NASA Modern Era Retrospective-Analysis for Research and Applications (MERRA2). This reanalysis is an upgrade of the original MERRA reanalysis with improved numerical representation of dynamics and parameterizations, improved 0.5 degree by 0.625 degree resolution, and improvements to the forcing data sets.

Reference
(in draft)