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| Titel |
Antarctic ice-mass balance 2003 to 2012: regional reanalysis of GRACE satellite gravimetry measurements with improved estimate of glacial-isostatic adjustment based on GPS uplift rates |
| VerfasserIn |
I. Sasgen, H. Konrad, E. R. Ivins, M. R. Broeke, J. L. Bamber, Z. Martinec, V. Klemann |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 7, no. 5 ; Nr. 7, no. 5 (2013-09-25), S.1499-1512 |
| Datensatznummer |
250085163
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| Publikation (Nr.) |
 copernicus.org/tc-7-1499-2013.pdf |
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| Zusammenfassung |
| We present regional-scale mass balances for 25 drainage basins of the
Antarctic Ice Sheet (AIS) from satellite observations of the Gravity and
Climate Experiment (GRACE) for time period January 2003 to September 2012.
Satellite gravimetry estimates of the AIS mass balance are strongly
influenced by mass movement in the Earth interior caused by ice advance and
retreat during the last glacial cycle. Here, we develop an improved
glacial-isostatic adjustment (GIA) estimate for Antarctica using newly
available GPS uplift rates, allowing us to more accurately separate
GIA-induced trends in the GRACE gravity fields from those caused by current
imbalances of the AIS. Our revised GIA estimate is considerably lower than
previous predictions, yielding an estimate of apparent mass change of
53 ± 18 Gt yr−1. Therefore, our AIS mass balance of −114 ± 23 Gt yr−1 is less
negative than previous GRACE estimates. The northern Antarctic Peninsula
and the Amundsen Sea sector exhibit the largest mass loss (−26 ± 3 Gt yr−1
and −127 ± 7 Gt yr−1, respectively). In contrast, East Antarctica exhibits
a slightly positive mass balance (26 ± 13 Gt yr−1), which is, however, mostly
the consequence of compensating mass anomalies in Dronning Maud and Enderby
Land (positive) and Wilkes and George V Land (negative) due to interannual
accumulation variations. In total, 6% of the area constitutes about half
the AIS imbalance, contributing 151 ± 7 Gt yr−1 (ca. 0.4 mm yr−1) to global
mean sea-level change. Most of this imbalance is caused by ice-dynamic speed-up expected to prevail in the near future. |
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