Developments have been made in accurate wave modelling. The third generation WAM wave model was extensively tested and technically and physically improved. The final cycle 4.0 version has become the standard model. It has been implemented operationally, together with the required archiving and diagnostic software.
The cycle 4.0 of the WAM model is organised as a subroutine version. It needs less computer resources than previous cycles. New options such as nesting, depth and current refraction have been added.
New input and dissipation source functions have been developed and introduced into cycle 4.0. The new physics takes into account that the wind and, therefore, the momentum flux through the sea surface is sea state dependent. Tests with atmospheric and surge models coupled with the WAM model have demonstrated the benefits.
The model was extensively verified against buoy and satellite altimeter measurements. Cycle 4.0 of the wave model forced by T213 wind fields of the European Centre for Medium Range Weather Forecasts (ECMWF) agrees very well with buoy and satellite wave height data.
A wave and wind data assimilation system based on optimal interpolation was further developed and combined with the wave model. Using careful tuning, a more prolonged impact of the measured data was obtained, and better wave forecasts produced.
The combined wave prediction and assimilation system is ready for operational use. It was successfully applied in a quasioperational mode during the calibration/validation phase of ERS1 to monitor the performance of the satellites' altimeter.
It is proposed to implement the third generation wave model developed by the WAM group on the ECMWF computer system in order to gain experience in the application of the model to global wave forecasting and to the assimilation of satellite data. Such a model will make it possible to exploit the great potential for improved ocean-wave forecasting offered by the first European Ocean Remote Sensing Satellite ERS-1 in 1989 and similar satellites planned by the US and Japan.
Funding SchemeCSC - Cost-sharing contracts
3730 AE De Bilt
RG12 2SZ Bracknell