An ERA40-based atmospheric forcing for global ocean circulation models

By L. Brodeau, B. Barnier, A. Treguier, T. Penduff, S. Gulev. 2010

453 citations recorded by the source corpus.

We develop, calibrate and test a dataset intended to drive global ocean hindcasts simulations of the last five decades. This dataset provides surface meteorological variables needed to estimate air-sea fluxes and is built from 6-hourly surface atmospheric state variables of ERA40. We first compare the raw fields of ERA40 to the CORE.v1 dataset of Large and Yeager (2004), used here as a reference, and discuss our choice to use daily radiative fluxes and monthly precipitation products extracted from satellite data rather than their ERA40 counterparts. Both datasets lead to excessively high global imbalances of heat and freshwater fluxes when tested with a prescribed climatological sea surface temperature. After identifying unrealistic time discontinuities (induced by changes in the nature of assimilated observations) and obvious global and regional biases in ERA40 fields (by comparison to high quality observations), we propose a set of corrections. Tropical surface air humidity is decreased from 1979 onward, representation of Arctic surface air temperature is improved using recent observations and the wind is globally increased. These corrections lead to a significant decrease of the excessive positive global imbalance of heat. Radiation and precipitation fields are then submitted to a small adjustment (in zonal mean) that yields a near-zero global imbalance of heat and freshwater. A set of 47-year-long simulations is carried out with the coarse-resolution (2° × 2°) version of the NEMO OGCM to assess the sensitivity of the model to the proposed corrections. Model results show that each of the proposed correction contributes to improve the representation of central features of the global ocean circulation.

Subfields: Atmospheric Science, Global and Planetary Change, Oceanography

View Paper: https://www.semanticscholar.org/paper/e88cb534bc42206c7e60c3e819c238ab03669ce1

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Citations in the corpus

JRA-55 based surface dataset for driving ocean–sea-ice models (JRA55-do) (2018, methodology): “…evaluation indicated that the surface fields of JRA-55 must be adjusted (bias-corrected locally and modified globally to impose flux balances) similarly to the NCEP/NCAR reanalysis in the CORE dataset and the ECMWF reanalysis in the DRAKKAR forcing set (Brodeau et al., 2010) (see also Fig.”
Improved Atlantic winter blocking in a climate model (2011, methodology): “The fluxes were calculated using bulk formulae and the DRAKKAR 4.1 forcing dataset, derived from ERA 40 reanalyses [Brodeau et al., 2010].”
The North Atlantic subpolar circulation in an eddy-resolving global ocean model (2015, background): “1 surface forcing (Brodeau et al., 2010), and 75 vertical levels.”
Sea Level Expression of Intrinsic and Forced Ocean Variabilities at Interannual Time Scales (2011, background): “1)] in Brodeau et al. (2010).”
Strong and moderate nonlinear El Niño regimes (2016, unknown): “0 ocean general circulation model with observational surface boundary conditions based on ERA40 reanalysis, as detailed in (Brodeau et al. 2010).”