The TOPAZ Arctic monitoring and prediction system

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Ocean data assimilation systems allow combining remote-sensing and in-situ ocean observations with primitive equations ocean general circulation models (OGCM). They thus provide initial conditions for short-term ocean currents forecasts (ten days to one month) and boundary conditions to nested high-resolution models of coastal seas and can be operated in hindcast to reproduce past events over long periods. At the time when the 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), coupled with different biogeochemical modules and data assimilation with the Ensemble Kalman Filter (EnKF). The paper presents validation results of the system and applications in nested regional models.