Hindcasting coastal sea levels in Morecambe Bay

A method of variational data assimilation (by means of an adjoint model) is used to improve the boundary conditions for a high resolution depth-averaged two dimensional non-linear hydrodynamic model of Morecambe Bay. The modelled region contains a large inter-tidal area and has an unusually high tidal range. The assimilation procedure is robust and effective in reducing model error. This system performs considerably better than the previous simple method used for assimilating data into the same numerical model. Height errors as low as 10 cm (root mean square) can be achieved. (C) 2001 Academic Press.