Near yearlong time series measurements of water level elevation from seven stations along the Suwannee River, Florida, were used to characterize, observationally and analytically, the propagation of tidal and subtidal signals along the estuary resulting from tide‐river interactions. Tidal amplitudes and phases were obtained from least squares fits to observed values and used to compare to an analytical model. Subtidal amplitude and phases were characterized by Hilbert empirical orthogonal functions (HEOFs), obtained through complex principal component analysis, and compared to an analytical solution. The landward attenuation of the tidal signal was replicated analytically. The subtidal signal (periods > tides) was also described analytically with an oceanic wave moving landward and a seaward river pulse. The subtidal analytical solution reproduced the competition between the landward and seaward waves and the zone where each wave dominated over the other. Depending on the phase of these landward and seaward subtidal waves, the resulting subtidal signal amplitude could either (a) attenuate landward to a certain location and then increase or (b) amplify landward up to a certain zone and then decrease.
24 January 2022 in Regional Studies in Marine Science
Estimates of turbulence properties with Acoustic Doppler Current Profiler (ADCP) measurements can be muddled by the influence of wave orbital velocities. Previous methods—Variance Fit, Vertical Adaptive Filtering (VAF), and Cospectra Fit (CF)—have tried to eliminate wave-induced contamination. However, those methods may not perform well in relatively energetic surface gravity wave or internal wave conditions. The Harmonic Analysis (HA) method proposed here uses power spectral density to identify waves and least squares fits to reconstruct the identified wave signals in current velocity measurements. Then, those reconstructed wave signals are eliminated from the original measurements. Datasets from the northeastern Gulf of Mexico and Cape Canaveral, Florida, are used to test this approach and compare it with the VAF method. Reynolds stress estimates from the HA method agree with the VAF method in the lower half of the water column because wave energy decays with depth. The HA method performs better than the VAF method near the surface during pulses of increased surface gravity wave energy.
3 December 2025 in Estuarine, Coastal and Shelf Science