Forecasting ocean waves

The role of the wave modelling team at the Met Office is to develop and maintain global, regional and coastal wave forecast models that allow accurate forecasts of sea-state to be issued within computing and delivery time budgets. Model configurations are based upon the National Centres for Environmental Prediction (NCEP) community model WAVEWATCH III^®, which allows the Met Office team to contribute to and benefit from the efforts of a worldwide group of research and development scientists.

The main challenge facing modellers running global and large regional models, that are necessarily run to capture swell from distant storms, is to provide information that is quantitatively accurate in shelf sea and near-coastal zones where the majority of marine users are based. The models aim to represent the growth, dissipation and transport of wind energy imparted to the sea-surface, and although modern 3^rd generation models parameterize each of these processes explicitly improvements in these representations are still sought. Translating the wave energy spectrum (the distribution of ocean wave energy in frequency and direction space) into statistics that can be sensibly interpreted by a range of forecasters and marine users is a less glamorous, but nonetheless vital and evolving aspect of our work.

Wave models explicitly calculate the transfer of momentum from the atmosphere to the ocean surface. Traditionally the models have been employed solely as a downstream tool for predicting sea-state, but the potential clearly exists to feedback this information to atmospheric NWP models in order to positively impact the traditional atmospheric weather forecast.

Key aims

• Develop and maintain a world leading operational global wave forecast model configuration.
• Develop and maintain a high accuracy regional wave forecast model(s) for UK shelf seas and coastal areas.
• Develop the wave model to ensure that sea-state specification in a coupled atmosphere-ocean NWP system will have maximum positive benefit.
• Provide the best available support and technical advice to core forecast users.
• Contribute to and draw benefits from the worldwide wave model development community.

Current projects

•  Development and testing of grid schemes for application with WAVEWATCH III^®.

• Sensitivity testing of shallow water wave physics for configurations of WAVEWATCH III^® covering shelf seas and macrotidal coastal regions.

• Comparison of model codes that downscale wave data from offshore to nearshore environments (shallow tidal waters to seaward edge of the surf zone).

• Developing application of the wave model to coupled atmosphere-ocean systems.