Data and Code for the ICESat-2 GRACE-FO Joint Mass Balance Analysis

Code_Package.zip Contains all the code necessasary to complete the entire analysis presented by Medley et al. (submitted) and provides access points for external code dependencies. The user should begin with 0 - Satellite altimetry-gravimetry fusion precisely quantifies ice-sheet atmospheric and dynamic changes.md, which provides the high level overview of the organization of the code and its structure. Details of the data dependencies and requirements are detailed in each of the three workflow markdown files, which should help guide the user through the analysis. Additional non-public data used in the workflow(s) are provided in Auxiliary_Data.zip. 1 - ICESat-2 Ice Sheet Elevation Analysis Pipeline.md This pipeline processes satellite altimetry data from ICESat-2 to create spatiotemporally gridded ice elevation datasets for ice sheet mass balance research. The complete workflow transforms raw along-track height measurements from ATL06 and ATL11 products into monthly, 10km resolution ice elevation grids that support joint analysis with GRACE-FO gravimetry data and surface process models (GSFC-FDM, GEMB, and IMAU-FDM) to solve for firn densification processes and separate atmospheric versus dynamic drivers of ice sheet mass balance. 2 - ICESat-2 GRACE-FO Joint Mass Balance Analysis Pipeline.md This 12-step pipeline combines ICESat-2 elevation data with GRACE-FO gravimetry observations to decompose ice sheet mass balance into its constituent components. By leveraging multiple climate models (GSFC-FDM, GEMB, and IMAU-FDM) and Monte Carlo simulations, the pipeline: Separates ice dynamics from surface mass balance signals Quantifies firn air content evolution Accounts for solid Earth elastic deformation Provides comprehensive uncertainty estimates Delivers monthly, 10km-resolution mass balance components The workflow builds upon the ICESat-2 monthly gridded elevation products (from the previous pipeline) and applies sophisticated statistical techniques including EOF analysis, elastic corrections, and constrained inversions to produce comprehensive mass balance estimates for Greenland and Antarctica ice sheets. 3 - Medley et al. Tables and Figures.md This 10-step process loads the data necessary to analyze our newly derived MASS, FAC, SMB, and DYN components of mass and volume change through fusion of ICESat-2 laser altimetry and GRACE/GRACE-FO gravimetry. After loading the results, the code steps through the generation of key tables and figures used in the manuscript. Finally, all 200 gridded partitions of MASS, FAC, SMB, and DYN for each model and each ice sheet are output to netCDF files for public distribution. Greenland outputs are provided within this repository (gris_partition_ensembles.zip); however, due to size limitations, the Antarctic files are available at https://nasagov.box.com/s/kkx46lp153anezroeo3k92frpelcjmdl. Auxiliary_Data.zip The data provided here are necessary to complete the ICESat-2 GRACE-FO Joint Mass Balance Analysis Pipeline. The authors generated these datasets to support the workflow, and they are not currently publically available. We do not provide other necessary datasets that are publically available. The dataset includes: JPL_RL06_GSM_ICE6G-D_[ais/gris]_cmwe_L60_r250km_004-288.nc: GRACE and GRACE-FO mass change with GIA correction from Peltier et al. (2017: https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016JB013844) processed onto the ICESat-2 10 km x 10 km grid. IMBIE2: catchment masks for the ICESat-2 10 km x 10 km grid using the Mouginot et al. (2017: https://doi.org/10.5067/AXE4121732AD, Mouginot and Rignot (2019: https://doi.org/10.7280/D1WT11) and Zwally: Zwally et al. (2012: https://imbie.org/imbie-2016/drainage-basins/) smb.FGRN055_1957-2020_BN_RACMO2.3p2_Monthly.nc: The Greenland RACMO2.3p2 Monthly SMB used to force the IMAU-FDM (https://zenodo.org/records/15830307). The data are not publicly available elseswhere but are being provided with permission of the creators. ATL15_[AA/GL]_10km_003_GIA_ICE6G-D_VM5a_O512_L256.nc: GIA height corrections for ICESat-2 from Peltier et al. (2017: https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016JB013844) processed onto the ICESat-2 10 km x 10 km grid. GRACE and GRACE-FO Uncertainty Grids as described in Sutterley et al. (2020: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019EA000860) ATM_PS_RMS_[ais/gris]_cmwe_L60_r250km.nc --> atmospheric pressure OBP_RMS_[ais/gris]_cmwe_L60_r250km.nc --> ocean bottom pressure SLF_RMS_[ais/gris]_cmwe_L60_r250km.nc --> sea level fluctuations TWS_RMS_[ais/gris]_cmwe_L60_r250km.nc --> terrestrial water storage ICE6G_VM5_RMS_[ais/gris]_cmwe_L60_r250km.nc --> glacial isostatic adjustment JPL_RL06_GSM_[ais/gris]_cmwe_L60_r250km_ERR_004-263.nc --> harmonics error IS2_Binary_IceMask_[ais/gris]_L60_r250km.nc: the mass threshold mask used to define the GRACE/GRACE-FO polar stereographic grid cells to use in our analysis (see Fig. S12). It was generated by applying a GRACE-like processing to a binary mask of 1’s that identifies the ICESat-2 ATl15 10 km cells that are ice covered. Gkernel_PREM_L40000_10km.nc: Green's function kernel for iterative assessment of the elastic rebound component of height change. IS2_PSscale_[ais/gris].nc: Areas of each of the polar stereographic grid cells associated with GRACE/GRACE-FO polar stereographic grids used in this analysis. G250.shp: Shapefile containing Greenland land boundaries from Kort & Matrikelstyrelsen (1998) moa[cl/gl]2009.mat: Coastlines and groundlines derived from MODIS Mosaic of Antarctica 2008-2009 (MOA2009) Image Map, Version 1. These are used for plotting purposes only. gris_partition_ensembles.zip A collection of MASS, SMB, DYN, and FAC partitions for the Greenland Ice Sheet for each model used in the analysis (GSFC, GEMB, IMAU) that contain 200 ensemble members for each partition. The grids contain polar stereographic x and y coordinates as well as the monthly decimal years for each time step. In total, each file is 154 (x) x 274 (y) x 83 (time) x 200 (ensemble). The grids are 10 km x 10 km, are identical to the ATL15 10 km grid, and have NSIDC Sea Ice Polar Stereographic North (EPSG 3413) projected coordinates. The associated Antarctic outputs are available at https://nasagov.box.com/s/kkx46lp153anezroeo3k92frpelcjmdl. The only differences from Greenland are that each file dimensions are 546 (x) x 446 (y) x 83 (time) x 200 (ensemble), and they use Antarctic Polar Stereographic (EPSG 3031) projection.