The Wider Loch Linnhe System Model

The Wider Loch Linnhe System (WLLS) model is an implementation of the Finite Volume Community Ocean Model (FVCOM) and has a domain covering many of the Inner Hebrides from the southern tip of the Mull of Kintyre to the Isle of Skye in the north. The western boundary extends to approximately 7.5° W from Northern Ireland to the southern Outer Hebrides. The model grid is unstructured with the highest horizontal resolution in Loch Linnhe, Loch Leven and Loch Sunart, where the node spacing goes down to 15 m.  The typical node spacing of these sea lochs is around 50 – 100 m, with  Lower Loch Linnhe having a typical node spacing of 100 – 150 m. Beyond Loch Linnhe, its side lochs, and Loch Sunart, the unstructured grid resolution reduces further, with the node spacing at the western boundary being around 5 km. The water column is resolved using a hybrid sigma layer scheme with 10 standard terrain following sigma layers, each representing 10% of the water column, in water depths shallower than 13 m. In areas deeper than 13 m. the water column is resolved with 2 fixed layers at the surface, each 1 m. thick, 2 fixed layers at the bottom, each 2.5 m. thick, and 6 sigma layers of equal spacing for the mid depths. This enables the freshwater output from Upper Loch Linnhe to be well resolved.

The main output from the model to date is a one year 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 WLLS model is nested within the wider SSM. Climatological atmospheric forcing and freshwater input were also applied to the model. The wider SSM has a 1993 tidal component included, which was then applied to the WLLS climatology. The latest version of the climatology is WLLS 1.02.

This information page is part of the theme: 
The Scottish Shelf Model
The model domain and node spacing of the Wider Loch Linnhe System model

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, WLLS 1.01 was replaced by WLLS 1.02.

Version Number Time Period Description Boundary Forcing Atmospheric Forcing Fresh Water Forcing FVCOM Version DOI
WLLS 1.01 1 year climatology representing 1960 - 2004 Original WLLS grid with climatological forcing The wider SSM version 1.01 Climatology derived from ECMWF ERA-40 and ERA-Interim (1960-2004) Grid2Grid climatology (1962-2011) 3.1.6  
WLLS 1.02 1 year climatology representing 1990 - 2014 Original WLLS grid with updated climatological forcing The wider SSM version 2.01 Climatology derived from ECMWF ERA-Interim (1990-2014) Grid2Grid climatology (1962-2011)  

10.7489/12043-1
WLLS 1.03 3 year hindcast 2011 - 2013 Original WLLS grid with new hindcast forcing. AMM7 daily mean reanalysis with the tide added from a harmonic analysis of archived AMM7 forecast data.

WRF 1/18° resolution supplied by CEH [1, 2]

 Grid2Grid river discharge climatology (1962-2011), River temperature climatology applied based on data from the Scotland River Temperature Monitoring Network [3].    
WLLS 1.04 2021 hindcast Original WLLS grid with new 2021 hindcast forcing and initial conditions from AMM15. AMM15 WRF 1/18° resolution supplied by CEH [1, 2] Grid2Grid river discharge climatology (1962-2011), River temperature climatology applied based on data from the Scotland River Temperature Monitoring Network [3].    

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). Some reduced precision model outputs of selected variables are available for download by following the links in the data sources table below and/or following the DOI links.

References:

[1] Vieno, M., Heal, M. R., Williams, M. L., Carnell, E. J., Nemitz, E., Stedman, J. R., and Reis, S.: The sensitivities of emissions reductions for the mitigation of UK PM2.5, Atmos. Chem. Phys., 16, 265-276, 10.5194/acp-16-265-2016, 2016.

[2] Vieno, M., Heal, M. R., Hallsworth, S., Famulari, D., Doherty, R. M., Dore, A. J., Tang, Y. S., Braban, C. F., Leaver, D., Sutton, M. A., and Reis, S.: The role of long-range transport and domestic emissions in determining atmospheric secondary inorganic particle concentrations across the UK, Atmos. Chem. Phys., 14, 8435-8447, 10.5194/acp-14-8435-2014, 2014.

[3] F. L. Jackson, I. A. Malcolm, David M. Hannah; A novel approach for designing large-scale river temperature monitoring networks. Hydrology Research 1 June 2016; 47 (3): 569–590. doi: https://doi.org/10.2166/nh.2015.106

Tuesday, August 23, 2022 - 17:31

Links and Resources

Type Title External link
Marine Scotland Data Portal The Scottish Shelf Model. Part 5: Wider Loch Linnhe Sub-Domain data.marine.gov.scot