Second order tidally induced flow in the inlet of a coastal lagoon

Abstract

Current meter data obtained in Indian River Inlet and Indian River Bay, Delaware are analyzed to compute second order low-frequency tidal flow and tidally induced mean flow in the system. Results from least-squares harmonic analysis show that nonlinearly induced M 4 currents in the inlet and bay occur at order 10 −1 of the M 2 amplitudes, indicating weak nonlinearity in the system. Tidally rectified mean flow computed from M m and M sf is ∼3 cm s −1, which is of the same order of magnitude as the observed mean current. The estimated low-frequency tidal flow and the tidally induced mean flow agree well with scalings computed for the inlet and with results found by Münchow et al. [Münchow, A., Masse, A.K., Garvine, R.W., 1992. Astronomical and nonlinear tidal currents in a coupled estuary shelf system. Continental Shelf Research 12, 471–498] in Delaware Bay.