Brief communication: Impact of common ice mask in surface mass balance estimates over the Antarctic ice sheet

• Published in: The Cryosphere
• Main Authors: Hansen, Nicolaj, Simonsen, Sebastian B., Boberg, Fredrik, Kittel, Christoph, Orr, Andrew, Souverijns, Niels, van Wessem, J. Melchior, Mottram, Ruth
• Format: Article in Journal/Newspaper
• Language: English
• Published: COPERNICUS GESELLSCHAFT MBH 2022
• Subjects: Antarctic; The Antarctic; Antarc*; Ice Sheet; The Cryosphere
• Online Access: http://nora.nerc.ac.uk/id/eprint/532267/; https://nora.nerc.ac.uk/id/eprint/532267/1/tc-16-711-2022.pdf; https://doi.org/10.5194/tc-16-711-2022

Regional climate models compute ice sheet surface mass balance (SMB) over a mask that defines the area covered by glacier ice, but ice masks have not been harmonised between models. Intercomparison studies of modelled SMB therefore use a common ice mask. The SMB in areas outside the common ice mask, which are typically coastal and high-precipitation regions, is discarded. Ice mask differences change integrated SMB by between 40.5 and 140.6 Gt yr(-1) (1.8 % to 6.0 % of ensemble mean SMB), equivalent to the entire Antarctic mass imbalance. We conclude there is a pressing need for a common ice mask protocol.