A note on the geostrophic velocity field referenced to a point

An alternative to the Dynamic Method for determining the geostrophic flow over shallow, irregular bathymetry is presented. The steric heights of water columns are computed by integrating the density from the surface to the bottom and then along bathymetric fall lines to a deepest common point. By assuming that the bottom pressures along these fall lines are isostatically adjusted, the steric height distribution can be converted into an adjusted sea-level distribution by using the deepest common point as a reference. The total pressure difference between two water columns is then available for conversion to geostrophic flow. An example of an application of the method to data from the Northern Adriatic, together with a discussion of the uncertainties involved, is given.