Dataset DOI: 10.5061/dryad.xd2547dvb

Description of the data and file structure

The data provided here is organized into 2 folders and 1 .mat file: Results and Figures. The file TG_Initialize_Transient_500mBed_NGlaDS.mat contains the model state just prior to running the model relaxation for the simulation using effective pressure from GlaDS and the 500-meter resolution bed topography. This file contains all fields and initial conditions necessary to launch the transient simulation corresponding to this bed and effective pressure combination. It includes results from the inversion and thermal model steps, as well as all required parameter values.

Model_Forcing: DATA_repo.zip

Results

This folder contains all relatent model output used in our analysis organized into 6 subfolders: Bed, Geometry, GL, SGH, VAF, and Vel. All files containing model results are named to identify the variable contained in the file, the bed resolution used in the model simulation, and the representation of subglacial hydrology (SGH) used where "Coupled" indicates synchronous coupling between the ice dynamics and subglacial hydrology modules, "NGlaDS" indicates effecitve pressure from steady state GlaDS, and "Nparam" indicates effective pressure approximated from the assumption of perfect connectivity to the ocean.

• Bed: 3 files (Bed_5km.mat, Bed_100m.mat, and Bed_500m.mat) containing the bed topography data at the 3 spatial resolutions used in this work projected onto our modeling domain. All bed topography is reported in meters and positive values indicate a bed height above sea-level.

• Geometry: 18 files containing the final model output, corresponding to simulation year 2300, for the base of the glacier (Base) and ice thickness (H) for each of the 9 model simulations. All geometry values are reported in meters, and negative values indicate meters below sea-level.

• GL: contains two subfolders (Exp and MAT), 1 MATLAB script (get_GL_intersections.m), 3 additional .mat files, and 1 .exp file. The MAT folder contains the grounding line location at various check points throughout the simulations for each of the 9 bed/SGH combinations. Grounding line location is saved for the years 2015, 2050, 2100, 2150, 2200, 2250, and 2300. This folder contains a total of 63 files. MATLAB files describing the grounding line location are converted to .exp files, which are saved in the Exp folder. There are 63 .exp files with matching naming convention to their corresponding MATLAB files. The .exp files are generated using an ISSM function called isoline.m. The following is an example of its usage:

>> GL = load('GL_100mBed_Coupled_2015.mat');
>> Contour = isoline(md, GL, 'value', 0, 'output', 'GL_100mBed_Coupled_2015.exp');

The .exp files are used in plotting functions to generate the manuscript figures. They are also used by the function get_GL_intersections.m to calculate the x-y position in Polar Stereographic coordinates where the modeled GL intersects with a central flowline of Thwaites at various times during the simulation. The flowline coordinates are contained in the file labled Thwaites_FL_GL.exp, and the calculated intersections are contained in the 3 files GL_intersection_N_Coupled.mat, GL_intersection_N_GlaDS.mat, and GL_intersection_N_POC.mat.

• SGH: 6 files containing results for the subglacial hydrology model output from the steady state GlaDS simulations for each of the 3 bed topographies used. Files labeled with h correspond to the thickness of the distributed sheet of subglacial water in units of meters. Files labeled with S correspond to the channelized discharge in units of cubic meters per second.

• VAF: 18 files containing timeseries data of the ice volume above floatation for each of the 9 model simulations. VAF files contain the ice volume (cubic meters) timeseries and files labled with time contain the corresponding model times (years) of each data point.

• Vel: 9 files containing the final velocity corresponding to simulation year 2300 for all three model runs. Files are labeled to indicate the parameter combination of its simulation, and velocity is reported in units of meters per year.

Figures

This folder contains one subfolder labeled Exp and 5 plotting scripts corresponding to each of the 5 figures in the main document. Plotting scripts will pull results from the relevant subdirectory in the Results folder, and supplemental data files (domain outline, Thwaites flowline, etc) from the Figures/Exp subfolder, and then generate and save figures shown in the main manuscript. There is one plotting script per paper figure, and they each require the parameterized model TG_Initialize_Transient_500mBed_NGlaDS.mat to be loaded in MATLAB on a computer with ISSM installed before running. The following is an example of their usage using MATLAB in the terminal:

>> md = loadmodel('TG_Initialize_Transient_500mBed_NGlaDS.mat');
>> cd Figures
>> plot_context(md);