Search

Surface topography across the marginal zone of the Greenland Ice Sheet is constantly evolving in response to changing weather, season, climate, and ice dynamics. However, current digital elevation models (DEMs) for the ice sheet are usually based on data from a multi-year period, thus obscuring these changes over time. Here we present four 500 m resolution summer DEMs (PRODEMs) of the Greenland Ice Sheet marginal zone for 2019 through 2022. The PRODEMs cover the marginal zone from the ice edge to 50 km inland, hence capturing all Greenland outlet glaciers. Each PRODEM is based on data fusion of CryoSat-2 radar altimetry and ICESat-2 laser altimetry using regionally varying kriging of elevation anomalies relative to ArcticDEM. The PRODEMs are validated using leave-one-out cross-validation, and PRODEM19 is further validated against an external data set, showcasing their ability to correctly represent surface elevations within the associated spatially varying prediction uncertainties. We observe a general lowering of surface elevations during the 4-year PRODEM period, but the spatial pattern of change is highly complex and with annual changes superimposed. The PRODEMs enable detailed studies of the marginal ice sheet elevation changes. With their high spatio-temporal resolution, the PRODEMs will be of value to a wide range of researchers and users studying ice sheet dynamics and monitoring how the ice sheet responds to changing environmental conditions. PRODEMs from summer 2019 through 2022 are available at 10.22008/FK2/52WWHG (Winstrup, 2024), and we plan to annually update the product henceforth. [ABSTRACT FROM AUTHOR]

Surface topography across the marginal zone of the Greenland Ice Sheet is constantly evolving in response to changes in weather, season, climate and ice dynamics. Yet current Digital Elevation Models (DEMs) for the ice sheet are usually based on data from a multi-year period, thus obscuring these changes over time. We here present four 500-meter resolution annual (2019-2022) summer DEMs of the Greenland ice sheet marginal zone (PRODEMs). The PRODEMs cover 50km wide band from the ice edge, and they capture all outlet glaciers of the Greenland ice sheet. Each PRODEM is based on data fusion of CryoSat-2 radar altimetry and ICESat-2 laser altimetry using a regionally-varying Kriging method. They are validated using leave-one-out cross-validation, showcasing their ability to correctly represent surface elevations within the associated spatially varying prediction uncertainties, which have a median value of 1.4m. We observe a general lowering of surface elevations compared to ArcticDEM, but the spatial pattern of change is highly complex and with annual changes superimposed. The PRODEMs will enable studies of the marginal ice sheet elevation changes in great detail, temporally as well as spatially. With their high spatio-temporal resolution, the PRODEMs will be of value to a wide range of researchers and users studying ice sheet dynamics and monitoring how the ice sheet responds to changing environmental conditions. Incorporating the PRODEM surface elevations in estimates of the solid ice discharge from Greenland outlet glaciers will e.g. improve our assessment of the mass balance of the Greenland ice sheet and its interannual variability. PRODEMs from summers 2019 through 2022 are available at https://doi.org/10.22008/FK2/52WWHG (Winstrup, 2023), and we plan to annually update the product henceforth. [ABSTRACT FROM AUTHOR]