SUBTIDAL SEA-LEVEL FLUCTUATIONS IN A LARGE FJORD SYSTEM

A cross-spectral analysis is made of subtidal (0.01-0.5 cpd) sea level (SSL), atmospheric pressure and wind fluctuations observed during 1966-1988 in the southern reaches of the fjord system formed by the Straits of Juan de Fuca/Georgia and Puget Sound. It shows that observed SSL can be largely explained by quasi-steady inverse barometer compensation to atmospheric pressure and the propagation of adjusted sea level fluctuations from the nearby continental shelf, with some local weather forcing in summer. Variations in coherence, amplitudes and relative phase between seasons, locations and frequencies support previous work that both barotropic and baroclinic processes have important influences on SSL within the fjord system.