6 - Tides in Coastal Seas and Basins

Summary

This chapter focuses on tides in coastal seas and basins, where nonlinear and frictional effects are generally important. The depth-averaged shallow-water constituents are derived (Appendix B). The origin of shallow-water constituents is explained. A simple example is analyzed of tidal flow over a bank to explain the principles behind tide-induced residual circulation. Implications for chaotic stirring are discussed. Co-oscillation and resonance in tidal basins are analyzed for simple configurations, including the effects of frictional and radiation damping. The Helmholtz oscillator is explained.Finally, the focus shifts from depth-averaged currents to the vertical structure (Ekman dynamics, tidal straining, strain-induced periodic stratification in estuaries). The decomposition of tidal currents in phasors (rotary components) is elucidated.