Modelling ocean surfaces

The majority of the surface of the earth is ocean and therefore the ocean/atmosphere interface is very important.  The wave model (ECWAM) provides information on sea-surface roughness and hence momentum loss in the boundary layer flow. The dynamic ocean model (NEMO) provides information on the sea-surface temperature.  Changes in these parameters as the forecast progresses impact strongly on monthly or seasonal forecasting.  This is particularly important with respect to El Niño/La Nina (ENSO) or other similar developments.

The state of the ocean surface can change on a daily time-scale.  Changes in the extent or movement of sea-ice, or modification of the structure of the upper ocean after the passage of hurricanes have an impact on the boundary energy and momentum interactions (e.g. a tropical cyclone can cool the sea surface through turbulent upwelling of colder water, particularly if the cyclone is slow-moving and/or the ocean's mixed layer is shallow).

Oceanic information is now derived in much the same way for all IFS model configurations.

For a variety of reasons coastal regions are important for many customers.  Seas immediately adjacent to coastlines are difficult for the oceanic models (NEMO) to analyse or forecast, so coastal areas are dealt with by FLake as if they were salty water lakes.  Heat, moisture and momentum fluxes are evaluated according to the proportion of the area of the grid box that is covered by open water defined by the Land-Sea Mask.  Where there is:

Tides are not considered.