Deterministic Forecasts

Deterministic forecasts of the ocean have only become available in relatively recent times (Bell et al. 2000). Nevertheless, rapid progress has been made over the last decade, including the introduction of eddy-resolving models and the assimilation of new observational data. See Brassington (Brassington 2010) for a comprehensive review of progress in operational ocean forecasting. In Australia, the BLUElink ocean forecasting system commenced routine forecasting operations in August 2007 (Brassington et al. 2007). Provided sufficient observational data is available, deterministic forecasts should have relatively small errors at the start of the forecast period. These errors will grow more slowly than persistence forecast errors, because the deterministic model is able to keep up with changes in the state of the ocean, by modelling its dynamic processes (see Fig 22.7b, Martin (2010)). Deterministic forecasts from systems such as BLUElink are highly detailed, providing variables such as temperature, salinity, currents and sea surface height at high spatial resolution for forecast periods of several days. They represent a huge advance on the persistence and climatological forecasts used by navies for many decades. In one sense, however, their strength is also their weakness, since it is difficult to transmit the high volumes of oceanic data now available from deterministic ocean forecasting systems from shore to ships and submarines, due to the bandwidth limitations of naval communications systems.

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