On stratification, barotropic tides, and secular changes in surface\n tidal elevations: Two-layer analytical model

In this study the influence of stratification on surface tidal elevations in\na two-layer analytical model is examined. The model assumes linearized,\nnon-rotating, shallow-water dynamics in one dimension with astronomical forcing\nand allows for arbitrary topography. Using a natural modal separation, both\nlarge scale (barotropic) and small scale (baroclinic) components of the surface\ntidal elevation are shown to be comparably affected by stratification. It is\nalso shown that the topography and basin boundaries affect the sensitivity of\nthe barotropic surface tide to stratification significantly. This paper,\ntherefore, provides a framework to understand how the presence of\nstratification impacts barotropic as well as baroclinic tides, and how climatic\nperturbations to oceanic stratification contribute to secular variations in\ntides. Results from a realistic-domain global numerical two-layer tide model\nare briefly examined and found to be qualitatively consistent with the\nanalytical model results.\n