DOI: 10.7280/d1kd7c
title: Data from: Widespread grounding line retreat of Totten Glacier, East Antarctica, over the 21st century

description: Totten Glacier, the primary ice discharger of East Antarctica, contains
 3.85 m sea level rise equivalent ice mass (SLRe) and has displayed
 ocean-driven dynamic change since at least the early 2000s. We project
 Totten’s evolution through 2100 in a fully coupled ice-ocean model, forced
 at the ocean boundaries with anomalies in CMIP6 projected temperature,
 salinity, and velocity. Consistent with previous studies, the Antarctic
 Slope Current continues to modulate warm water inflow towards Totten in
 future simulations. Warm water (-0.5-1oC) accesses Totten’s sub-ice shelf
 cavity through depressions along the eastern ice front, driving sustained
 retreat of Totten’s eastern grounding zone that cannot be captured in
 uncoupled models. In high emission scenarios, warm water overcomes
 topographic barriers and dislodges Totten’s southern grounding zone around
 2070, increasing the rate of grounded ice loss 3.5-fold (10 to 35 Gt/yr)
 and resulting in a total 4.20 mm SLRe loss by 2100. In this data
 publication, we present the model output and results associated with the
 Geophysical Research Letter's manuscript 2021GL093213:
 “Widespread grounding line retreat of Totten Glacier, East Antarctica,
 over the 21st century”. We include all coupled and uncoupled ice sheet
 model results and the initial-state ice sheet model. In addition, we
 include the temperature, salinity and velocity mean rate-of-change fields
 that were applied to the northern, eastern, and western ocean boundaries
 following CMIP6 low and high emission scenarios. We also include example
 ocean model output from the initial ocean model state and at 2070 for all
 coupled experiments, an ocean model data file that details the setup and
 grid of the ocean model, and the ocean model bathymetry and initial ice
 shelf draft files. Lastly, we include the time series of the mean strength
 of the Antarctic Slope Current for all couped experiments, as well as the
 script used to facilitate coupling between the ice sheet and ocean model.
 Please note that we do not include all ocean model output, as the number
 and size of the associated files is too large; however, the data available
 here is sufficient to reproduce all manuscript figures and recreate the
 model-coupling.
description: <strong>Ice sheet model results</strong>: Direct
 results taken from the Ice-sheet and Sea-level System Model (Larour et al.
 2012) with no processing applied, given bi-monthly.
 <strong>Ocean model results</strong>: Direct results
 taken from the MIT General Circulation Model (MITgcm, Marshall and Clarke,
 1997) with no processing applied.
 <strong>Strength of the Antarctic Slope
 Current</strong>: The east-west component of the ocean velocity
 (direct output of the MITgcm) was averaged at 118<sup>o</sup>C
 along the continental slope at depths between 280-820 m from January 1,
 2017 to December 15, 2099 (bi-weekly).
 <strong>Ice shelf draft</strong>: Direct output from
 BedMachine Antarctica (Morlighem et al., 2020) over ice covered regions of
 the ocean model domain, no processing has been applied.
 <strong>Ocean bathymetry</strong>: Bathymetry below
 floating ice is taken from BedMachine Antarctica (Morlighem et al., 2020)
 and from ETOPO1 over open ocean (National Geophysical Data Center), with
 recent updates of more accurate bathymetry for the region on the
 continental shelf off Totten ice shelf from Rintoul et al. (2016). Data
 was linearly interpolated between the different data sets to allow for a
 smooth transition. <strong>Ocean boundary forcing
 files</strong>: Monthly CMIP6 projected ocean temperature (T),
 salinity (S), east-west velocity (U), and north-south velocity (V) was
 extracted along the ocean model boundaries (northern, eastern, and
 western) between January 2017 and December 2100 following low (SSP126) and
 high (SSP585) emission scenarios from four global climate models:
 CNRM-CM6-1, CNRM-ESM2-1, UKESM1-0-LL, and MIROC-ES2L. At every grid cell
 along a given boundary, we compute the rate of change of a given field
 between 2017 and 2100, providing us with rates of change in ocean T, S, U,
 and V for each global climate model. At each boundary, we then
 model-average of these rate of change fields with respect to a specific
 variable. In the end, we are provided with anomalies in T, S, U, and V at
 the eastern, western, and northern ocean model boundaries.