Aspects of the Tidal Variability Observed on the Southern California Continental Shelf

Abstract Observations of the current and temperature field from the southern California continental shelf are analyzed in a frequency band (0.6–6 cpd) dominated by tidal fluctuations. The seasonal variability of the temperature and horizontal velocity component fields for this frequency band is characterized both in terms of mean variance statistics and change in the power spectra. The most striking seasonally varying feature is the O(102) increase in tidal band temperature variance observed from winter to summer on the inner shelf. Energetic cuspate peaks are observed centered at 1, 2, 3 and 4 cpd. The bandwidth of the peaks is approximately 0.2 cpd giving a decorrelation time of 5 days for tidally-induced current and velocity component fluctuations. A complex empirical eigenfunction analysis indicates that the amplitude and phase of coherent structures in the velocity component and temperature fields vary over vertical and horizontal spatial scales comparable to the local depth and shelf width respectiv...