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| Titel |
A range correction for ICESat and its potential impact on ice-sheet mass balance studies |
| VerfasserIn |
A. A. Borsa, G. Moholdt, H. A. Fricker, K. M. Brunt |
| 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 ; 8, no. 2 ; Nr. 8, no. 2 (2014-03-03), S.345-357 |
| Datensatznummer |
250116072
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| Publikation (Nr.) |
 copernicus.org/tc-8-345-2014.pdf |
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| Zusammenfassung |
| We report on a previously undocumented range error in NASA's Ice, Cloud and
land Elevation Satellite (ICESat) that degrades elevation precision and
introduces a small but significant elevation trend over the ICESat mission
period. This range error (the Gaussian-Centroid or "G-C" offset) varies on a
shot-to-shot basis and exhibits increasing scatter when laser transmit
energies fall below 20 mJ. Although the G-C offset is uncorrelated over
periods ≤ 1 day, it evolves over the life of each of ICESat's three
lasers in a series of ramps and jumps that give rise to spurious elevation
trends of −0.92 to −1.90 cm yr−1, depending on the time period considered.
Using ICESat data over the Ross and Filchner–Ronne ice shelves we show that
(1) the G-C offset introduces significant biases in ice-shelf mass balance
estimates, and (2) the mass balance bias can vary between regions because of
different temporal samplings of ICESat. We can reproduce the effect of the
G-C offset over these two ice shelves by fitting trends to sample-weighted
mean G-C offsets for each campaign, suggesting that it may not be necessary
to fully repeat earlier ICESat studies to determine the impact of the G-C
offset on ice-sheet mass balance estimates. |
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