The Pentland Firth and Orkney Waters Model
The Pentland Firth and Orkney Waters (PFOW) is an important region for marine renewable energy, and features prominently in the National Marine Plan. For example, this region significantly contributes to the total Scottish tidal stream resource. The PFOW model is an implementation of the Finite Volume Community Ocean Model (FVCOM) and has a domain covering the northern Isles of Orkney and Shetland and Moray Firth, extending from approximately 0° - 5° W and 57° - 61° N. The model grid is unstructured with the highest horizontal resolution in the Pentland Firth where the typical node spacing is 100 – 150 m. Away from Orkney the model has a comparably low horizontal resolution. The vertical water column is resolved using 10 terrain-following sigma layers, each representing 10% of the water column.
The main output from the model to date is a one year long Climatology representing typical present day conditions (1990-2014). For this climatology, the model was forced by the wider Scottish Shelf Model (SSM) climatology at the open boundary. Effectively, the PFOW is nested within the wider SSM. Climatological atmospheric forcing and fresh water input were also applied to the model. The wider SSM has a 1993 tidal component included, which was then applied to the PFOW climatology. The latest version of the climatology is PFOW 1.02. A number of other model runs have been performed, for specific time periods, and these are listed in the table below.
![](https://marine.gov.scot/sites/default/files/styles/large/public/ssm_pfow_model_domain_transparent.png?itok=BCefTg7y)