Ice-shelf basal melting in a global finite-element sea-ice/ice-shelf/ocean model

• Published in: Annals of Glaciology
• Main Authors: Timmermann, R., Wang, Q., Hellmer, H.H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: International Glaciological Society 2012
• Subjects: Amundsen Sea; Getz; Getz Ice Shelf; Southern Ocean; Weddell; Weddell Sea; Annals of Glaciology; Antarc*; Antarctica; Ice Shelf; Ice Shelves; Sea ice
• Online Access: https://oceanrep.geomar.de/id/eprint/49688/; https://oceanrep.geomar.de/id/eprint/49688/1/iceshelf_basal_melting_in_a_global_finiteelement_seaiceiceshelfocean_model.pdf; https://doi.org/10.3189/2012AoG60A156

The Finite Element Sea-ice Ocean Model (FESOM) has been augmented by an ice-shelf component with a three-equation system for diagnostic computation of boundary layer temperature and salinity. Ice-shelf geometry and global ocean bathymetry have been derived from the RTopo-1 dataset. A global domain with a triangular mesh and a hybrid vertical coordinate is used. To evaluate sub-ice-shelf circulation and melt rates for present-day climate, the model is forced with NCEP reanalysis data. Basal mass fluxes are mostly realistic, with maximum melt rates in the deepest parts near the grounding lines and marine ice formation in the northern sectors of the Ross and Filchner–Ronne Ice Shelves, Antarctica. Total basal mass loss for the ten largest ice shelves reflects the importance of the Amundsen Sea ice shelves; the Getz Ice Shelf is shown to be a major meltwater contributor to the Southern Ocean. Despite their modest melt rates, the ‘cold water’ ice shelves in the Weddell Sea are still substantial sinks of continental ice in Antarctica. Discrepancies between the model and observations can partly be attributed to deficiencies in the forcing data or to (sometimes unavoidable) smoothing of ice-shelf and bottom topographies.