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.

This information page is part of the theme: 
The Scottish Shelf Model
(a) The Pentland Firth and Orkney Waters model domain and (b) the unstructured grid for the region around the Orkney Islands.

Model Runs and Versions

The model versions/runs listed each have a different computational grid and/or use different forcing data. This is reflected in the version numbering convention where the first number indicates the grid version and the second indicates the model run and/or the forcing data used. Rows where the text is grey indicate that the model version has been surpassed with a later version, usually listed directly below. For example, PFOW 1.01 was replaced by PFOW 1.02. Model runs in italics indicate that the data are not currently available.

Version Number Time Period Description Boundary Forcing Atmospheric Forcing Fresh Water Forcing DOI
PFOW 1.01 1 year climatology representing 1960 - 2004 Original PFOW grid with climatological forcing The wider SSM climatology version 1.01 Climatology derived from ECMWF ERA-40 and ERA-Interim (1960-2004) Grid2Grid climatology (1962-2011)  
PFOW 1.02 1 year climatology representing 1990 - 2014 Original PFOW grid with updated climatological forcing The wider SSM climatology version 2.01 Climatology derived from ECMWF ERA-Interim (1990-2014) Grid2Grid climatology (1962-2011) 10.7489/12041-1
PFOW 1.03.1 July 2013 - October 2014 Model run for the period of time the BRAHAN HF radar system, covering the Fair Isle Gap, was operational Atlantic Margin Model (AMM7) 7 km resolution ECMWF ERA-Interim Grid2Grid climatology (1962-2011)  
PFOW 1.03.2 July 2013 - October 2014 Model run for the period of time the BRAHAN HF radar system, covering the Fair Isle Gap, was operational, with no fresh water forcing Atlantic Margin Model (AMM7) 7 km resolution ECMWF ERA-Interim None  
PFOW 1.03.3 July 2013 - October 2014 Model run for the period of time the BRAHAN HF radar system, covering the Fair Isle Gap, was operational, with no atmospheric forcing Atlantic Margin Model (AMM7) 7 km resolution None Grid2Grid climatology (1962-2011)  

If you are interested in any of these models, or the model outputs, please contact the Marine Scotland Science Oceanography group (mss.oceanography@gov.scot).

Friday, March 4, 2022 - 12:03

Links and Resources

Type Title External link
Documents A modelling study of the tidal stream resource of the Pentland Firth, Scotland doi.org
Marine Scotland Data Portal The Scottish Shelf Model. Part 2: Pentland Firth and Orkney Waters Sub-Domain data.marine.gov.scot