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| Titel |
Continental mass change from GRACE over 2002-2011 and its impact on sea level |
| VerfasserIn |
O. Baur, Michel Kuhn, W. E. Featherstone |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250067834
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| Zusammenfassung |
| Present-day continental mass variations as observed by space gravimetry reveal secular mass
decline and accumulation. Whereas the former contribute to sea-level rise, the latter result in
sea-level fall. As such, consideration of mass accumulation (rather than focussing solely on
mass loss) is important for reliable overall estimates of sea-level change. Using data from the
Gravity Recovery And Climate Experiment (GRACE) satellite mission, we quantify
mass-change trends in 20 continental areas that exhibit a dominant signal. During the integer
nine-year period May 2002 to April 2011, (GIA-adjusted) mass gain and mass
loss in these areas contributed, on average, to -(0.79 ± 0.25) mm/yr of uniform
sea-level fall and +(1.80 ± 0.18) mm/yr of uniform sea-level rise. The net effect
was +(1.01 ± 0.31) mm/yr. Ice melting over Greenland, Antarctica, Alaska and
Patagonia was responsible for +(1.28 ± 0.18) mm/yr of the total balance. Hence,
land-water mass accumulation compensated about 20% of the impact of ice-melt
water influx to the oceans. In order to assess the impact of geocentre motion, we
converted geocentre coordinates derived from Satellite Laser Ranging (SLR) to
degree-one geopotential coefficients. We found geocentre motion to introduce small
systematic biases to mass-change and sea-level change estimates. Its overall effect is
+(0.12 ± 0.05) mm/yr, but mainly compensates part of the sea-level fall contribution to the
total sea-level change budget. This value, however, should be taken with care owing to
questionable reliability of secular trends in SLR-derived geocentre coordinates. |
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