Melting of ice shelves and the mass balance of Antarctica

We calculate the present ice budget for Antarctica from measurements of accumulation minus iceberg calving, run-off and in situ melting beneath the floating ice shelves. The resulting negative mass balance of 469 Gt year−1 differs substantially from other recent estimates but some components are subject to high temporal variability and budget uncertainties of 20–50%. Annual accumulation from an earlier review is adjusted to include the Antarctic Peninsula for a total of 2144 Gt year−1. An iceberg production rate of 2016 Gt year−1 is obtained from the volume of large icebergs calculated from satellite images since 1978, and from the results of an international iceberg census project. Ice-shelf melting of 544 Gt year−1 is derived from physical and geochemical observations of meltwater outflow, glaciological field studies and modeling of the sub-ice ocean circulation. The highest melt rates occur near ice fronts and deep within sub-ice cavities. Run-off from the ice-sheet surface and from beneath the grounded ice is taken to be 53 Gt year−1. Less than half of the negative mass balance need come from the grounded ice to account for the unattributed 0.45 mm year−1 in the IPCC “best estimate” of the recent global sea-level rise.

Details

Publication status:
Published
Author(s):
Authors: Jacobs, S.S., Helmer, H.H., Doake, C.S.M., Jenkins, A. ORCID, Frolich, R.M.

On this site: Adrian Jenkins
Date:
1 January, 1992
Journal/Source:
Journal of Glaciology / 38
Page(s):
375-387
Digital Object Identifier (DOI):
https://doi.org/10.3189/S0022143000002252