Tide surge models can provide good approximations to the
astronomical and surge tides in an area.

While not as good as
predictions based on gauge data (model predictions accurate to better
than 10 cm are possible at present), their geographical coverage is
better, so predictions are available at high resolution (typically
better than 50m, but limited by the resolution of the
bathymetry).

Surge models are forced by tidal and wind data.
Hindcast wind stress data from the ECMWF or NCEP reanalysis
(extending back for decades) can be used to represent
historical surges and extract surge climatology. Surge elevations
at the model resolution can be produced for long periods and these
can then be used to produce surge and extreme level statistics for a
given location. It is also possible to use met forecasts to give
surge predictions.

Models used include Telemac 2d and 3d, ADCIRC,
and the Princeton Ocean Model, This model is driven by a global tidal
model and ECMWF or NCEP reanalysis meteorological data. For
example, we have used Telemac2d with a finite element grid with
resolution of about 200m near selected coastal sites, while the
Princeton Ocean Model has been implemented with a typical resolution
at the coast of 1-5km. Model performance is optimised using
feedback between the coastal tides and the boundary tides and
bathymetry.

For wave climatologies, wind data and data from global wave models can also be used to drive wave models at shelf and local scales. Such models may be coupled with tidal models. Models used include Swan and Tomawac (which couples directly with Telemac2d).

Wave devices maybe included in such models as an absorbtion / energy loss term at the locations of wave devices: this can be extended to enable a simple representation of wave arrays. A more realistic representation of wave devices represents a device in terms of absorption and radiation of energy; single devices have been included in standard wave models, and in diffraction models such as the refdif model.

Here, elevation and flow data from the large scale model is
applied using innovative assimilation and correction techniques to
drive small scale local models. Tidal and surge elevations accurate
to better than 10cm are feasible using this technique.

Again, long
term simulations are possible, to retrieve surge statistics for a
given area; alternatively surge forecasting systems can be produced.

**Possible work**

-2D and 3D models of flow and elevation,
give elevation and depth average flows,

-Choice of tidal
models

-Choice of wave models

--Tidal prediction based on
model results

-Hindcasts of tide/surge elevations

-Wave
prediction and wave climate

-analysis of wave data