A high-resolution Antarctic grounding zone product from ICESat-2 laser altimetry

• Published in: Earth System Science Data
• Main Authors: Li, Tian, Dawson, Geoffrey J, Chuter, Stephen J, Bamber, Jonathan L
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Zenodo 2022
• Subjects: Amundsen Sea; Antarc*; Antarctic; Filchner Ronne Ice Shelf; Filchner-Ronne Ice Shelf; Ice Sheet; Ice Shelf; National Snow and Ice Data Center; Ronne Ice Shelf; Ross Ice Shelf
• Online Access: https://doi.org/10.5194/essd-14-535-2022

The Antarctic grounding zone, which is the transition between the fully grounded ice sheet to freely floating ice shelf, plays a critical role in ice sheet stability, mass budget calculations, and ice sheet model projections. It is therefore important to continuously monitor its location and migration over time. Here we present the first ICESat-2-derived high-resolution grounding zone product of the Antarctic Ice Sheet, including three important boundaries: the inland limit of tidal flexure (PointF), inshore limit of hydrostatic equilibrium (PointH), and the break in slope (PointI b ). This dataset was derived from automated techniques developed in this study, using ICESat-2 laser altimetry repeat tracks between 30March2019 and 30September2020. The new grounding zone product has a near-complete coverage of the Antarctic Ice Sheet with a total of 21 346 PointF, 18 149 PointH, and 36 765 PointI b locations identified, including the difficult-to-survey grounding zones, such as the fast-flowing glaciers draining into the Amundsen Sea embayment. The locations of newly derived ICESat-2 landward limit of tidal flexure agree well with the most recent differential synthetic aperture radar interferometry (DInSAR) observations in 2018, with a mean absolute separation and standard deviation of 0.02 and 0.02 km, respectively. By comparing the ICESat-2-derived grounding zone with the previous grounding zone products, we find a grounding line retreat of up to 15 km on the Crary Ice Rise of Ross Ice Shelf and a pervasive landward grounding line migration along the Amundsen Sea embayment during the past 2 decades. We also identify the presence of ice plains on the Filchner–Ronne Ice Shelf and the influence of oscillating ocean tides on grounding zone migration. The product derived from this study is available at https://doi.org/10.5523/bris.bnqqyngt89eo26qk8keckglww (Li et al., 2021) and is archived and maintained at the National Snow and Ice Data Center.