Observationally constrained surface mass balance of Larsen C Ice Shelf, Antarctica

• Main Authors: Kuipers Munneke, Peter, McGrath, Daniel, Medley, Brooke, Luckman, Adrian, Bevan, Suzanne, Kulessa, Bernd, Jansen, Daniela, Booth, Adam, Smeets, Paul, Hubbard, Bryn, Ashmore, David, Van den Broeke, Michiel, Sevestre, Heidi, Steffen, Konrad, Shepherd, Andrew, Gourmelen, Noel
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Antarctic; Antarctic Peninsula; Antarc*; Antarctica; Ice Shelf
• Online Access: http://livrepository.liverpool.ac.uk/3076763/; https://doi.org/10.5194/tc-2017-44; http://livrepository.liverpool.ac.uk/3076763/1/tc-2017-44.pdf

<jats:p>Abstract. Combining several geophysical techniques, we reconstruct spatial and temporal patterns of surface mass balance (SMB) over Larsen C Ice Shelf (LCIS), Antarctic Peninsula. Continuous time series of snow height at five locations allow for multi-year estimates of seasonal and annual SMB over LCIS. There is high interannual variability, with an SMB of 395 ± 61 to 413 ± 42 mm w.e. y−1 in the north and a larger SMB of up to 496 ± 50 mm w.e. y−1 farther south. This difference between north and south is corroborated by winter snow accumulation derived from an airborne radar survey from 2009, which showed an average snow thickness of 0.95 m north of 76° S, and 1.12 m south of 78°. Analysis of ground-penetrating radar from several field campaigns allows for a longer-term perspective of spatial SMB: a particularly strong and coherent reflection horizon below 25–44 m w.e. of ice and firn is observed in radargrams collected across the shelf. We propose that this horizon was formed in a single melt season over the ice shelf. Combining ground and airborne radar with SMB output from a regional climate model confirms that SMB increases from north to south, overprinted by a gradient of increasing SMB to the west. Previous observations show a strong decrease in firn air content toward the west, which we attribute to spatial patterns of melt, refreezing, and densification, rather than SMB. </jats:p>