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Abstract The heat transfer between the warm oceanic water and the floating portion of the Antarctic ice sheet (the ice shelves) occurs in a dynamic environment with year‐to‐year changes in the distribution of icebergs and fast‐ice (the “icescape”). Dramatic events such as the collapse of glacier tongues are apparent in satellite images but oceanographic observations are insufficient to capture the synoptic impact of such events on the supply of oceanic heat to ice shelves. This study uses a 3D numerical model and semi‐idealized experiments to examine whether the current high melting rates of ice shelves in the Amundsen Sea could be mitigated by certain icescape configurations. Specifically, the experiments quantify the impacts on oceanic heat supply of presence/absence of the Thwaites Glacier Tongue, Bear Ridge Iceberg Chain, tabular iceberg B22, and fast‐ice cover seaward of Pine Island Ice Shelf (PIS). The experiments reveal that future changes in the coastal icescape are unlikely to reverse the high ice shelf melting rates of the Amundsen Sea, and that icescape changes between 2011 and 2022 actually enhanced them slightly. Ice shelves such as Crosson and Thwaites are found to have multiple viable sources of oceanic heat whose relative importance may shift following icescape reconfigurations but the overall heat supply remains high. Similarly, the formation of a fast‐ice cover seaward of PIS slows down the cavity circulation (by 7%) but does not reduce its heat supply. 

A 3-D numerical model was used for multi-decadal eddy-resolving simulations of the Amundsen Sea embayment (Antarctica). A control simulation covered the historical period 2006-2023 (~2 decades) under realistic atmospheric and oceanic conditions. Three additional simulations representing the mid-21st century were conducted based on future projections from CMIP6 models ACCESS-CM2, MPI-ESM1-2-HR, MRI-ESM2-0 (scenario SSP2-4.5). These three CMIP6 models were selected based on their realism during the historical period as well as their diversity in terms of resolution and level of warming. The four simulations provided information about the regional hydrography, oceanic circulation, sea ice cover, ice shelf basal melt rates, and biogeochemical conditions (nitrogen and iron). The four simulations were then condensed into daily climatologies in order to summarize changes in the seasonal cycle of the Amundsen embayment in response to the projected warming. The present archive includes the four daily climatologies as well as all the information required to repeat the numerical experiments (code and input files). 

Satellite images from Antarctica reveal important changes in the coastal icescape (fast-ice, icebergs and ice shelves) but these yearly changes and their impacts on the coastal circulation and ice shelf basal melt rates are not represented in the Earth System Models used to project future sea level rise. The impacts of these yearly icescape changes are thus investigated using a high-resolution regional ocean-ice shelves-sea ice coupled model of the Amundsen Sea (Antarctica). A set of nine semi-idealized experiments were designed to highlight the impacts of (a) the collapse of the Thwaites Glacier Tongue, (b) the disappearance of the Bear Ridge Iceberg Chain and tabular iceberg B22, and (c) presence/absence of a fast-ice cover between Thwaites and Pine Island ice shelves, in both cold and warm background hydrological conditions. The dataset features the results of the nine experiments and reveals changes in sea ice concentrations, coastal oceanic circulation and oceanic heat supply to the ice shelf cavities, ice shelf basal melt rates, hydrological conditions, and fluxes of heat/freshwater at the sea surface. These model results are archived in self-documented NetCDF files with the appropriate metadata for each variable. The dataset includes a 'readme file' providing an overview of the archive as well as additional information regarding the model results. 

A three-dimensional numerical model of the Amundsen Sea (Antarctica) was used to simulate the period Jan.2006-Mar.2022 under consistent atmospheric/oceanic forcings, bathymetry/ice shelf topography, and model equations/parameters. The model is an implementation of the Regional Ocean Modeling System (ROMS, https://www.myroms.org/) with extensions for sea ice (Budgell 2005) and ice shelves (Dinniman et al. 2011). It simulates the ocean hydrography and circulation, sea ice thermodynamics and dynamics, and the basal melt of the ice shelves, with a uniform horizontal mesh of 1.5km and 20 topography-following vertical levels. Forcings include the ERA5 reanalysis (3-hourly), 10 tidal constituents from CATS 2008, and ocean/sea ice conditions at the edges of the model domain taken from the 5km-resolution circumpolar model of Dinniman et al. 2020 and from daily SSM/I satellite images. The model outputs are divided into nine directories each containing two years worth of model results (run661-669) in the NetCDF format. Each directory contains: daily-averaged model fields (roms_avg_xxxx.nc), instantaneous snapshots every 3 hours for select fields (roms_qck_xxxx.nc), and instantaneous snapshots every 30 days (roms_his_xxxx.nc). All the metadata information necessary for the interpretation of the model outputs (dimensions, units, etc) is included inside the NetCDF files. The NetCDF files follow the CF conventions and can be opened with various software that are open source and freely available over the Internet. In addition to the model outputs, this archive includes the computer code as well as the input files necessary for reproducing the model outputs of this archive.