作者:Liu, Y (Liu, Yan)[ 1,2 ] ; Moore, JC (Moore, John C.)[ 1,2,3,4 ] ; Cheng, X (Cheng, Xiao)[ 1,2 ] ; Gladstone, RM (Gladstone, Rupert M.)[ 5,6 ] ; Bassis, JN (Bassis, Jeremy N.)[ 7 ] ; Liu, HX (Liu, Hongxing)[ 8 ] ; Wen, JH (Wen, Jiahong)[ 9 ] ; Hui, FM (Hui, Fengming)[ 1,2 ]

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PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

卷: 112  期: 11  页: 3263-3268

DOI: 10.1073/pnas.1415137112

出版年: MAR 17 2015

摘要

Iceberg calving from all Antarctic ice shelves has never been directly measured, despite playing a crucial role in ice sheet mass balance. Rapid changes to iceberg calving naturally arise from the sporadic detachment of large tabular bergs but can also be triggered by climate forcing. Here we provide a direct empirical estimate of mass loss due to iceberg calving and melting from Antarctic ice shelves. We find that between 2005 and 2011, the total mass loss due to iceberg calving of 755 +/- 24 gigatonnes per year (Gt/y) is only half the total loss due to basal melt of 1516 +/- 106 Gt/y. However, we observe widespread retreat of ice shelves that are currently thinning. Net mass loss due to iceberg calving for these ice shelves (302 +/- 27 Gt/y) is comparable in magnitude to net mass loss due to basal melt (312 +/- 14 Gt/y). Moreover, we find that iceberg calving from these decaying ice shelves is dominated by frequent calving events, which are distinct from the less frequent detachment of isolated tabular icebergs associated with ice shelves in neutral or positive mass balance regimes. Our results suggest that thinning associated with ocean-driven increased basal melt can trigger increased iceberg calving, implying that iceberg calving may play an overlooked role in the demise of shrinking ice shelves, and is more sensitive to ocean forcing than expected from steady state calving estimates.

通讯作者地址: Cheng, X (通讯作者)

Beijing Normal Univ, Coll Global Change & Earth Syst Sci, State Key Lab Remote Sensing Sci, Beijing 100875, Peoples R China.

地址:

[ 1 ] Beijing Normal Univ, Coll Global Change & Earth Syst Sci, State Key Lab Remote Sensing Sci, Beijing 100875, Peoples R China

[ 2 ] Joint Ctr Global Change Studies, Beijing 100875, Peoples R China

[ 3 ] Univ Lapland, Arctic Ctr, Rovaniemi 96100, Finland

[ 4 ] Uppsala Univ, Dept Earth Sci, S-75236 Uppsala, Sweden

[ 5 ] Univ Tasmania, Antarctic Climate & Ecosyst Cooperat Res Ctr, Hobart, Tas, Australia

[ 6 ] ETH, Versuchsanstalt Wasserbau Hydrol & Glaziol, CH-8093 Zurich, Switzerland

[ 7 ] Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA

[ 8 ] Univ Cincinnati, McMicken Coll Arts & Sci, Dept Geog, Cincinnati, OH 45221 USA

[ 9 ] Shanghai Normal Univ, Dept Geog, Shanghai 200234, Peoples R China