CORRELATIONS IN SEA-LEVEL ELEVATIONS

We have analyzed a 105-year time record of hourly sea-level elevations for the port of Esbjerg, Denmark. In addition to well-known periodic components, the power spectrum has a low-frequency broadband structure which we interpret as having three regimes behaving approximately as f(0), f(-1.2), and f(-2.4) with increasing frequency. We attribute thi s behavior to driven, damped Kelvin waves. In this context, we present a model which considers the correlation function of a damped wave equ ation driven by a spatially distributed noise source. We have also stu died shorter records at other locations which display similar spectra and compared the coherence functions with the model predictions.