Abstract
Measurements of currents during the 4-month period beginning June 1978 taken at three stations off Ste-Marthe-de-Gaspe in the Gulf of St. Lawrence were subject to time series analyses. Such time series were considered as superpositions of almost periodic and of stochastic components. Variations in the currents due to tidal forcing have been identified by spectral analysis, and both their amplitudes and relative contribution to the total variations were compared. Six cyclical components representing semidiurnal, diurnal and semi-monthly oscillations (M 2, S 2, N 2, K 1, O 1, M f ) have been selected using Mallows’ C P criterion and were incorporated in a harmonic polynomial model. The residual series of the previous adjustment were first tested for their mutual independency and for their stationarity. The backward difference operator was then applied to studentized residual series and then an ARMA model was fitted. It was found that the actual differenced residuals are related to those previous ones with time lags of 16, 17, 21, 33 or 34 hours. Such time lags do not correspond to any known tidal periodicities. It is suggested that other forcing, due to meteorological phenomena for example, seems to be contributing to the dynamics and variability of the Gaspe Current.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call