Towards improved real-time forecast modelling for the NW European shelf seas

The Met Office has run a 3-D circulation model of the NW European shelf seas in the daily suite of operational forecast models since June 2000, using the POLCOMS system implemented on a ~12 km grid, providing a nowcast and 2-day forecast. Inside this model are nested regional models of the Irish Sea region, at one nautical mile resolution, and the NW European Shelf to the 200 m contour (Medium Resolution Continental Shelf, MRCS), at ~6 km resolution, that were introduced in 2003 and early 2005, respectively. The MRCS model includes a basic representation of sediment transport. In addition, a coupled physical-ecological model on the MRCS domain using the POLCOMS-ERSEM system is running pre-operationally in near real time and is coupled to a fuzzy-logic based system to estimate risk of harmful algal blooms (HAB). A constant-density relocatable model can be applied in high resolution to any region of the shelf seas. Data from the models are available either via the Met Office Data and Products Distribution Service for operational purposes, or on request via ftp for research collaborations, and have been provided to many international research groups and projects. Modelled surface currents and winds have been used to force the VISAR and SARIS Search and Rescue (SAR) and OSIS Oil drift packages. Sediment and biogeochemical parameters from the ecological model are used to provide estimates of visibility. We focus on model validation and highlight areas where the models could be improved. Comparison with SST observed by moored buoys, the daily GHRSST Ocean Surface Temperature and Ice analysis (OSTIA) product and monthly temperature climatology indicate good agreement for the annual cycle of sea surface temperature in the North Sea and Irish Sea. However, in the continental margin region to the west of the UK there is a significant temperature deficit in the NW European Shelf model. This appears to result from errors in the simulation of the along-slope current that can be reduced by smoothing model bathymetr