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CoverNewton's Bulletin

Issue n. 3, January 2006   [pp. 104-115]

Identifying sea-level rates by a wavelet-based multiresolution analysis of altimetry and tide gauge data

E.V. Rangelova, R.S. Grebenitcharsky and M.G. Sideris

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Satellite altimetry offers opportunities for studying crustal motion of regional and local origins. This is achieved by the precise determination of the rate of change of the sea level from altimetry data combined with tide gauge records of relative sea level change. In this study, we investigate an application of a wavelet-based multiresolution analysis of TOPEX/Poseidon altimetry data (from 1992 to 2002) and tide gauge records to evaluate trends of sea level change in the Baltic Sea. We compare the sea level trends with those estimated viaa least-squares (LS) regression approach. The conducted numerical experiments demonstrate that, in contrast to the wavelet-based approach, LS regression tends to underestimate the sea level trends when short and noisy time series are analyzed. In the presence of an anomalous sea level signal, the wavelet-based approach can detect and model this signal and also accounts for this effect on the sea level trend.