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| Titel |
Practical analysis of tide gauges records from Antarctica |
| VerfasserIn |
Gaia Galassi, Giorgio Spada |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250104536
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| Publikation (Nr.) |
 EGU/EGU2015-3958.pdf |
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| Zusammenfassung |
| We have collected and analyzed in a basic way the currently available time series from tide
gauges deployed along the coasts of Antarctica. The database of the Permanent Service for
Mean Sea Level (PSMSL) holds relative sea level information for 17 stations, which are
mostly concentrated in the Antarctic Peninsula (8 out of 17). For 7 of the PSMSL stations,
Revised Local Reference (RLR) monthly and yearly observations are available,
spanning from year 1957.79 (Almirante Brown) to 2013.95 (Argentine Islands). For the
remaining 11 stations, only metric monthly data can be obtained during the time window
1957-2013. The record length of the available time series is not generally exceeding 20
years. Remarkable exceptions are the RLR station of Argentine Island, located
in the Antarctic Peninsula (AP) (time span: 1958-2013, record length: 54 years,
completeness=98%), and the metric station of Syowa in East Antarctica (1975-2012, 37
years, 92%). The general quality (geographical coverage and length of record) of the time
series hinders a coherent geophysical interpretation of the relative sea-level data
along the coasts of Antarctica. However, in an attempt to characterize the relative
sea level signals available, we have stacked (i.e., averaged) the RLR time series
for the AP and for the whole Antarctica. The so obtained time series have been
analyzed using simple regression in order to estimate a trend and a possible sea-level
acceleration. For the AP, the the trend is 1.8 ± 0.2 mm/yr and for the whole Antarctica it is
2.1 ± 0.1 mm/yr (both during 1957-2013). The modeled values of Glacial Isostatic
Adjustment (GIA) obtained with ICE-5G(VM2) using program SELEN, range between
-0.7 and -1.6 mm/yr, showing that the sea-level trend recorded by tide gauges
is strongly influenced by GIA. Subtracting the average GIA contribution (-1.1
mm/yr) to observed sea-level trend from the two stacks, we obtain 3.2 and 2.9
mm/yr for Antarctica and AP respectively, which are interpreted as the effect of
current ice melting and steric ocean contributions. By the Ensemble Empirical Mode
Decomposition method, we have detected different oscillations embedded in the sea-level
signals for Antarctica and AP. This confirms previously recognized connections
between the sea-level variations in Antarctica and ocean modes like the ENSO. |
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