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.代码包（Code_Package.zip）包含完成Medley等人（已投稿）研究中全部分析所需的代码，并提供外部代码依赖的接入端口。用户应从《0 - Satellite altimetry-gravimetry fusion precisely quantifies ice-sheet atmospheric and dynamic changes.md》开始阅读，该文档概述了代码的整体组织与架构。各数据依赖项与要求的详细说明见于三个工作流Markdown文件，它们将引导用户完成整个分析流程。本工作流中使用的部分非公开数据已打包至Auxiliary_Data.zip中。 1 - ICESat-2冰盖高程分析流程（1 - ICESat-2 Ice Sheet Elevation Analysis Pipeline.md） 该流程用于处理冰、云、陆地高程卫星2号（ICESat-2）卫星测高数据，以生成用于冰盖质量平衡研究的时空网格化冰高程数据集。完整工作流将ATL06与ATL11产品的原始沿轨高度测量值转换为分辨率10km的月度冰高程网格，可与重力恢复与气候实验后续任务（GRACE-FO）重力测量数据及地表过程模型（GSFC-FDM、GEMB、IMAU-FDM）联合分析，以反演积雪压实过程，并分离冰盖质量平衡的大气驱动因子与动力驱动因子。 2 - ICESat-2与GRACE-FO联合质量平衡分析流程（2 - ICESat-2 GRACE-FO Joint Mass Balance Analysis Pipeline.md） 该含12个步骤的流程将ICESat-2高程数据与GRACE-FO重力测量观测数据相结合，将冰盖质量平衡分解为各组成部分。通过利用多个气候模型（GSFC-FDM、GEMB、IMAU-FDM）与蒙特卡洛模拟，该流程可： - 将冰动力信号与表面质量平衡信号分离 - 量化积雪空气含量的演化过程 - 考虑固体地球弹性形变 - 提供全面的不确定性估计 最终生成分辨率10km的月度质量平衡组分数据。 该工作流基于前一流程生成的ICESat-2月度网格化高程产品，应用了包括经验正交函数（EOF）分析、弹性校正与约束反演在内的先进统计技术，为格陵兰与南极冰盖提供全面的质量平衡估算结果。 3 - Medley等人图表制作流程（3 - Medley et al. Tables and Figures.md） 该含10个步骤的流程加载所需数据，通过融合ICESat-2激光测高与GRACE/GRACE-FO重力测量数据，分析新推导的质量与体积变化组分（MASS、FAC、SMB、DYN）。加载结果后，代码将生成论文中使用的关键表格与图件。最后，所有模型、各冰盖的200个网格化MASS、FAC、SMB、DYN分区将输出至netCDF文件以供公开分发。格陵兰的输出文件已包含在本仓库中（gris_partition_ensembles.zip）；但受限于文件大小，南极相关文件可通过https://nasagov.box.com/s/kkx46lp153anezroeo3k92frpelcjmdl获取。 辅助数据压缩包（Auxiliary_Data.zip） 本压缩包包含完成ICESat-2与GRACE-FO联合质量平衡分析流程所需的数据。作者生成这些数据集以支持本工作流，目前尚未公开。本包不包含其他已公开的必要数据集。 本数据集包含： 1. JPL_RL06_GSM_ICE6G-D_[ais/gris]_cmwe_L60_r250km_004-288.nc：经Peltier等人(2017: https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016JB013844)提出的ICE6G-D模型进行冰川均衡调整（GIA）校正的GRACE与GRACE-FO质量变化数据，已重采样至ICESat-2的10km×10km网格。 2. IMBIE2：基于Mouginot等人(2017: https://doi.org/10.5067/AXE4121732AD)、Mouginot与Rignot(2019: https://doi.org/10.7280/D1WT11)及Zwally等人(2012: https://imbie.org/imbie-2016/drainage-basins/)的研究成果，制作的ICESat-2 10km×10km网格集水区分区掩码。 3. smb.FGRN055_1957-2020_BN_RACMO2.3p2_Monthly.nc：用于驱动IMAU-FDM模型的格陵兰RACMO2.3p2月度表面质量平衡（SMB）数据，该数据未在其他渠道公开，已经创作者许可提供。 4. ATL15_[AA/GL]_10km_003_GIA_ICE6G-D_VM5a_O512_L256.nc：经Peltier等人(2017: https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016JB013844)提出的ICE6G-D_VM5a模型处理得到的ICESat-2 GIA高程校正数据，已重采样至10km×10km网格。 5. GRACE与GRACE-FO不确定性网格：详见Sutterley等人(2020: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019EA000860) - ATM_PS_RMS_[ais/gris]_cmwe_L60_r250km.nc：大气压力不确定性网格 - OBP_RMS_[ais/gris]_cmwe_L60_r250km.nc：海底压力不确定性网格 - SLF_RMS_[ais/gris]_cmwe_L60_r250km.nc：海平面波动不确定性网格 - TWS_RMS_[ais/gris]_cmwe_L60_r250km.nc：陆地水储量不确定性网格 - ICE6G_VM5_RMS_[ais/gris]_cmwe_L60_r250km.nc：冰川均衡调整不确定性网格 - JPL_RL06_GSM_[ais/gris]_cmwe_L60_r250km_ERR_004-263.nc：球谐系数误差网格 6. IS2_Binary_IceMask_[ais/gris]_L60_r250km.nc：用于定义本分析中GRACE/GRACE-FO极方位投影网格单元的质量阈值掩码（见图S12）。该掩码通过对标识ICESat-2 ATL15 10km网格中冰覆盖区域的二进制1掩码进行类GRACE处理生成。 7. Gkernel_PREM_L40000_10km.nc：用于迭代评估高程变化弹性回弹组分的格林函数核。 8. IS2_PSscale_[ais/gris].nc：本分析中使用的GRACE/GRACE-FO极方位投影网格各单元的面积数据。 9. G250.shp：包含格陵兰陆地边界的形状文件，源自Kort & Matrikelstyrelsen(1998) 10. moa[cl/gl]2009.mat：源自2008-2009年MODIS南极马赛克（MOA2009）图像地图V1的海岸线与地线，仅用于绘图。 格陵兰分区集合压缩包（gris_partition_ensembles.zip） 本压缩包包含分析中使用的所有模型（GSFC、GEMB、IMAU）对应的格陵兰冰盖MASS、SMB、DYN与FAC分区数据，每个分区包含200个集合成员。网格包含极方位投影的x、y坐标，以及各时间步的月度十进制年份。单个文件的维度为154(x)×274(y)×83(时间)×200(集合成员)。网格分辨率为10km×10km，与ATL15 10km网格一致，采用NSIDC海冰极方位投影北坐标系（EPSG 3413）。 相关的南极输出文件可通过https://nasagov.box.com/s/kkx46lp153anezroeo3k92frpelcjmdl获取。与格陵兰数据集的唯一区别在于：单个文件维度为546(x)×446(y)×83(时间)×200(集合成员)，且采用南极极方位投影（EPSG 3031）坐标系。