This dataset contains model output from the fully coupled global Earth system model, ESM4, developed at the Geophysical Fluid Dynamics Laboratory (GFDL) of the National Oceanic and Atmospheric Administration (NOAA). The user of this dataset is referred to Adcroft et al. (2019) and the references therein for a detailed discussion of the GFDL-OM4.0 ocean / sea ice configuration used in ESM4 and Dunne et al. (2020) for a discussion of the fully coupled model configuration, model spin-up protocol, and model performance.

The model output format are compressed tar.gz files containing netcdf files chunked by 5 model years. The title of each tar.gz file lists the variable, model component, and time frequency as follows: esm4_tier1_antwater.variable.model_component_frequency.tar.gz. The ocean_monthly_z and ocean_annual_z output are provided as z depth levels in meters as opposed to the models native hybrid vertical ocean coordinate which consists of z* (quasi-geopotential) coordinates in the upper ocean through the mixed layer, transitioning to isopycnal (referenced to 2000 dbar) in the ocean interior.

This output was produced in coordination with the Southern Ocean Freshwater release model experiments Initiative (SOFIA) and is the Tier 1 experiment where freshwater is delivered in a spatially and temporally uniform pattern at the surface of the ocean at sea surface temperature in a 1-degree latitude band extending from Antarctica's coastline. The total additional freshwater flux imposed as a monthly freshwater flux entering the ocean is 0.1 Sv. Users are referred to the methods section of Beadling et al. (2022) for additional details on the meltwater implementation in ESM4.

This experiment branches from year 0001 of ESM4's piControl simulation already published and available on the CMIP6 Earth System Grid Federation Archive (https://esgf-node.llnl.gov/projects/esgf-llnl/; ) as part of the CMIP6 Diagnostic, Evaluation and Characterization of Klima (DECK) (Eyring et al., 2016) suite of experiments. Therefore, for appropriate comparison, users should compare results against years 0001 to 0100 in the published piControl simulation.

Additional details for each variable including units etc., can be found in the header information for each netcdf file. A summary table of all variables available in this dataset is provided as an additional .csv file. If a variable was requested for SOFIA but is not part of GFDL's standard post-processing procedure, it is noted in the table.

The simulations were performed by Rebecca Beadling (Current affiliation Temple University;  rebecca.beadling@temple.edu) with Stephen Griffies (stephen.griffies@noaa.gov) as the point of contact for any questions regarding the use of ESM4's model output and participation in SOFIA.

References:
Adcroft, A., and Coauthors, 2019: The GFDL global ocean and sea ice modle OM4.0: Model description and simulation features. J. Adv. Mod. Earth Sys., 11, 3167-3211.

Beadling, R. L., and Coauthors, 2022: Importance of the Antarctic Slope Current in the Southern Ocean response to ice sheet melt and wind stress change. J. Geophys. Res. Oceans, 127, e2021JC017608.

Dunne, J. P., and Coauthors, 2020: The GFDL Earth System Model Version 4.1 (GFDL-ESM4.1): Overall coupled model description and simulation characteristics. J. Adv. Mod. Earth Sys., 12, J. Adv. Mod. Earth Sys., 11, 3167-3211.

Eyring, V., and Coauthors, 2016: Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization. Geosci. Model Dev., 9, 1937-1958.

Krasting, J. P., and Coauthors, 2018: NOAA-GFDL GFDL-ESM4 model output prepared for CMIP6 CMIP piControl. Earth System Grid Federation.