Abstract:
This dataset contains output from a hydrodynamic model of the ocean in the Larsen C Ice Shelf (LCIS) cavity and a nearby area of the western Wedell Sea. Simulations were run using the MITgcm numerical ocean model and included an ice shelf with steady thickness. A new LCIS bathymetry was used in the simulations, referred to as the 'Brisbourne' bathymetry. The data provided here includes these geometry grids and ocean velocity and basal melt rate fields output from the final year of an arbitrary 10-year simulation, or a 6-month extension run. Calculated marine ice fields beneath the ice shelf based on the simulation's melt rate results are also included. In addition, output from several simulations using different initial and boundary ocean temperature conditions and runs with different cavity geometries are also provided.
This work was supported by the Natural Environment Research Council and the EnvEast Doctoral Training Partnership [grant number NE/L002582/1] and PICCOLO [grant number NE/P021395/1].
Keywords:
Ice shelf-ocean interactions, Larsen C Ice Shelf, Marine ice, Model validation, Ocean warming experiments
Harrison, L. (2022). Output from a numerical model of the ocean beneath Larsen C Ice Shelf, Antarctica (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/a54c795c-e0ee-49cb-99dd-befbdc4a70f0
| Access Constraints: | None. |
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| Use Constraints: | Data released under Open Government Licence V3.0: http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. |
| Creation Date: | 2022-02-01 |
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| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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| Personnel: | |
| Name | UK PDC |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Ms Lianne Harrison |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Parent Dataset: | N/A |
| Reference: | Harrison, L. C., Holland, P. R., Heywood, K. J., Nicholls, K. W., Brisbourne, A. M. Sensitivity of melting, freezing and marine ice beneath Larsen C Ice Shelf to changes in ocean forcing. Submitted to Geophysical Research Letters (2022). | |
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| Lineage: | Simulations were run using the MITgcm numerical ocean model, version c65z. The model featured an ice shelf with steady thickness and a new bathymetry created using natural neighbour interpolation of 114 seismic soundings in the LCIS cavity. The bathymetry was deepened to create a minimum water-column thickness of 40 m, the thickness of two full grid cells, to allow unhindered flow wherever the ice is known to be floating. The domain included the LCIS cavity and a small area of the western Weddell Sea, with a uniform grid resolution of 20 m in the vertical, 1/20° in longitude, and variable in latitude, scaled by the cosine of the latitude, resulting in isotropic grid cells of ~2 km width. Constant diffusivities of 10 m2/s in the horizontal and 10-4 m2/s in the vertical were used, and lateral and vertical eddy viscosity coefficients of 50 m2/s and 10-3 m2/s, respectively. A three-equation model was used to parameterise melting and freezing, with a drag coefficient of 0.0022 and heat and salt transfer coefficients of 0.011 and 3.1 x 10-4, respectively. Tides were implemented by imposing velocities on open boundaries to the north, east and south from the CATS2008 inverse tidal model. Constant ocean properties were imposed on the model boundaries with a potential temperature of -1.9°C and practical salinity of 34.5, the same values as the initial conditions. Further simulations with initial and boundary condition temperatures of -1.8°C, -1.6°C, and -1.4°C were also run, as well as alternative bathymetry simulations. The marine ice fields were calculated by assuming that modelled melt/freeze rates, and ice shelf velocities are fixed in time. These fields were interpolated onto a 100 m grid and then marine ice thickness was time-stepped on this grid for 500 years using a simple upwind advection scheme. | |
| Spatial Coverage: | |
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| Latitude | |
| Southernmost | -69.89 |
| Northernmost | -65.34 |
| Longitude | |
| Westernmost | -65.98 |
| Easternmost | -56.83 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | 0 m |
| Max Depth | -860 m |
| Data Resolution: | |
| Latitude Resolution | approx. 1/50 degree, ~2km |
| Longitude Resolution | 1/20 degree, approx. 2 km |
| Horizontal Resolution Range | N/A |
| Vertical Resolution | 20 m |
| Vertical Resolution Range | N/A |
| Temporal Resolution | N/A |
| Temporal Resolution Range | N/A |
| Location: | |
| Location | Antarctica |
| Detailed Location | Larsen C Ice Shelf |
| Data Storage: | Harrison2022_LCIS.nc - 8 MB Harrison2022_LCIS_marine_ice.nc - 786 MB Harrison2022_LCIS_tides.nc - 268 KB where Harrison2022_LCIS.nc - this file provides the model geometry (bathymetry, ice topography, water-column thickness), referred to as the 'Brisbourne' geometry, as well as melt rates, sub-ice velocities and sub-ice speeds for the three geometry cases: Brisbourne, Bedmap2 and Mueller, as detailed in the manuscript. The barotropic streamfunction for the 'standard run' (detailed in the manuscript) and the tides-only run are also found in this file. Additionally, melt rates for the warmer temperature cases are provided here. Harrison2022_LCIS_marine_ice.nc - this file contains the marine ice thickness fields calculated from the three geometry cases and warmer temperature runs. Harrison2022_LCIS_tides.nc - this file contains timeseries of tidal elevation at 6 locations in LCIS domain. |
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