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| Titel |
Evaluation of empirical mode decomposition for quantifying multi-decadal variations and acceleration in sea level records |
| VerfasserIn |
D. P. Chambers |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 22, no. 2 ; Nr. 22, no. 2 (2015-03-10), S.157-166 |
| Datensatznummer |
250120970
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| Publikation (Nr.) |
 copernicus.org/npg-22-157-2015.pdf |
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| Zusammenfassung |
| The ability of empirical mode decomposition (EMD) to
extract multi-decadal variability from sea level records is tested using
three simulations: one based on a series of purely sinusoidal modes, one
based on scaled climate indices of El Niño and the Pacific decadal
oscillation (PDO), and the final one including a single month with an
extreme sea level event. All simulations include random noise of similar
variance to high-frequency variability in the San Francisco tide gauge
record. The intrinsic mode functions (IMFs) computed using EMD were compared
to the prescribed oscillations. In all cases, the longest-period modes are
significantly distorted, with incorrect amplitudes and phases. This affects
the estimated acceleration computed from the longest periodic IMF. In these
simulations, the acceleration was underestimated in the case with purely
sinusoidal modes, and overestimated by nearly 100% in the case with
prescribed climate modes. Additionally, in all cases, extra low-frequency
modes uncorrelated with the prescribed variability are found. These
experiments suggest that using EMD to identify multi-decadal variability and
accelerations in sea level records should be used with caution. |
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