MC 5501
Speaker
William Xu, College of Earth, Ocean and Atmospheric Sciences, Oregon State University, USA
Title
Ocean Tides and Sea Level Fluctuations
Abstract
In the deep, open ocean, the astronomical tidal potential generates a vertically uniform body force across the water column, causing changes of water column mass and hence the propagation of barotropic tides. They are also known as the surface tides because their dynamics are manifested primarily at the sea surface in the form of sea level fluctuation. On the other hand, the interaction of barotropic tidal currents with the bottom topography perturbs the water column stratification, leading to the generation of baroclinic tides. They are also known as the internal tides because their dynamics are manifested primarily through the isopycnal displacement rather than the sea level fluctuation. Nevertheless, sea level anomalies associate with the baroclinic tides are non-trivial but visible from both satellite altimeter data and model output. In this talk I will describe a linear decomposition of the sea surface height, derived from the normal mode decomposition of the surface pressure, that consistently separates the large- and small-scale sea level anomalies associated with the barotropic and baroclinic tides, respectively. This decomposition provides a useful diagnostic of the tidal dynamics in observations and ocean models with a free surface.