The TOPAZ monitoring and prediction system for the Atlantic and Arctic Oceans

Ocean data assimilation systems allow the combination of remote sensing and in-situ ocean observations with primitive equation ocean general circulation models (OGCM). They thus provide initial conditions for short-term ocean currents forecasts (ten days to one month) and boundary conditions for nested high-resolution models of coastal seas and can be operated in hindcast to reproduce past events over long periods. At a time when offshore activities are moving toward deeper waters and ice-covered seas, accurate monitoring and forecasting of the environment (particularly ocean currents and sea-ice) cannot be neglected. This paper presents the TOPAZ system, being the Arctic component of the MERSEA integrated system and one of the contributors to the GODAE international initiative. The system is based on the latest scientific developments in terms of ocean modelling with the Hybrid Coordinate Ocean Model (HYCOM) and data assimilation with the Ensemble Kalman Filter (EnKF). Validation results of the system and applications in nested regional models are presented.