Description

This dataset contains the simulation results presented in:

Moore-Maley, B., J. McClean, A. Barthel, S. T. Gille, and L. Van Roekel. (2026). Subpolar North Atlantic water mass transformation and overturning in eddying and non-eddying simulations. J. Adv. Model. Earth Sys. [accepted] doi: 10.1029/2025MS005208

LA-UR-25-23544

A corresponding software repository can be accessed at doi: 10.5281/zenodo.18410552

Simulations

This dataset contains postprocessed simulations from forced, ocean-sea ice configurations of the DOE Energy Exascale Earth System Model (E3SM) Version 2 (Golaz et al., 2022). These configurations use the Model for Prediction Across Scales (MPAS) ocean and sea ice codes, originally described by Ringler et al., 2013 and Turner et al., 2022. Two E3SM simulations are included in this dataset:

1. GMPASLR A low-resolution, non-eddying simulation
   • Horizontal mesh ranging from 60 km at mid-latitudes to 30 km at the tropics and poles
   • 60 vertical layers ranging from 10 m thick at the surface to 250 m thick at depth
   • GM and Redi mesoscale eddy parameterizations with constant coefficients (kGM = 600 m2/s, kRedi=400 m2/s) and Brunt-Väisälä frequency scaling.
2. GMPASHR A high-resolution, eddying simulation
   • Horizontal mesh ranging from 18 km at the equator to 6 km at the poles
   • 80 vertical layers ranging from 2 m thick at the surface to 150 m thick at depth

The simulations were initialized from rest using temperature and salinity from the Polar science center Hydrographic Climatology version 2.0 (PHCv2, Steele et al., 2001), and 1~m thick sea ice "discs" extending from the poles to 70N and 60S. The simulations were forced using the Coordinated Ocean-ice Reference Experiments II (CORE-II) protocol (Griffies et al., 2009). The CORE-II forcing data are derived from observations and atmospheric reanalysis and span the 62-year period from 1948 to 2009. A surface salinity restoring flux was applied with a time scale of 1 yr. The configurations are summarized in the table below.

Subsetting

The simulation results included in this dataset are subsets of the full simulation output.

• Time This dataset includes monthly-averaged output for the following period:
  • Decades 1-6 (CORE-II years 1948-2008)
• Space This dataset is subset in space from the original global output according to the following constraints:
  • Top layer cell-centered variables
  • Select mixed-layer averaged variables (e.g., temperature, salinity, salinity tendencies)
  • Atlantic Ocean bounding box [100W, 45E, 35S, 85N]
• Variables The following preprocessed model variables are included on the native meshes
  • Potential density referenced to the surface
  • Potential temperature referenced to the surface
  • Salinity
  • Mixed-layer averaged potential temperature and salinity
  • Zonal and meridional velocity (resolved and GM+redi)
  • Sea surface height
  • Mixed layer depth (0.03 kg/m3 density threshold)
  • Sea ice area fraction
  • Surface heat flux variables (Total Radiative, Latent, Sensible, Seaice)
  • Surface freshwater flux variables (Evaporation, Precipitation, Runoff, Seaice)
  • Surface salt flux (Seaice)
  • Surface salinity flux (Restoring)
  • Mixed-layer averaged salinity tendencies due to advection, mixing, and surface flux (Seaice)

Postprocessing

This dataset contains multiple categories of postprocessing. These categories are designed to reduce the overall size of the dataset while aiding in the analysis of three specific regions: the Iceland-Rockall basins, the Irminger Sea, and the Labrador Sea. Additional regions are also included for further exploratory analysis: the Atlantic Ocean, the aggregate Irminger-Iceland Basins, and the Nordic Seas. The four categories are:

• Cell Fields These are the cell-centered model fields subset in space as described above
• Transect Fields These are fields from the original global results files that have been interpolated at selected transects. The transects together form complete boundaries for the six regions mentioned above. Two of the transects are chosen to overlap with the Overturning in the Subpolar North Atlantic Program (OSNAP) observing lines. The zonally-integrated meridional overturning circulation stream functions for the Atlantic basin (AMOC) in depth and potential density coordinates are also include in this category. The transects are as follows:
  • Barents Sea
  • Davis Strait
  • Denmark Strait
  • Fram Strait
  • Hudson Bay
  • Iceland-Faroe Ridge
  • North Sea
  • OSNAP East-Reykjanes
  • OSNAP East
  • OSNAP West
  • SAMBA
• Binned Quantities These are quantities that have been binned into discrete classes of potential density, potential temperature, salinity, and temperature-salinity (TS), for each of the six regions mentioned above. Cell-centered quantities (e.g., surface transformation, volume) are integrated over the region interior. Cell-edge quantities (e.g., transport) are integrated over the region boundaries.
• Budget Quantities These are quantities that have been averaged over the 3D mixed layer in each of the six regions to form a salinity budget. See the companion manuscript for further details.

Additional supporting data

Coordinates files and mapping weights files are also provided for each of the simulations. The coordinates files are subset over the same Atlantic Ocean bounding box [100W, 45E, 35S, 85N]. The mapping weights files are for the full global domain, so the subset cell-centered fields must be padded to the full domain prior to regridding. The geojson files that define the analysis regions are also provided.