1. Wind driven seasonal variations in the transport of NAW through the Faroe-Shetland Channel also acknowledge: European Commission (MOEN – ASOF EU-E, Framework V) Toby Sherwin Scottish Association for Marine Science, Oban Acknowledgements: Bill Turrell, Sarah Hughes, Bee Berx (Marine Scotland), Bogi Hansen (FFL), Svein Østerhus (UiB) based on: Sherwin, T.J., Hughes, S.L., Turrell, W.R., Hansen, B., Østerhus, S., 2008. Wind-driven monthly variations in transport and the flow field in the Faroe–Shetland Channel, Polar Research 27 (1), 7-22. Sherwin, T.J., Williams, M.O., Turrell, W.R., Hughes, S.L., Miller, P.I., 2006. A description and analysis of mesoscale variability in the Faroe-Shetland Channel. JGR 111, ISI:000235995000002 (C3).

2. Bathymetry of the Faroe – Shetland Channel NSDW + NAW MNAW

3. THE PROBLEM OF MESOSCALE VARIABILITY

4. Velocities and transport in the NAW at 4 ADCPs From different methodologies: Hughes et al., (2006) mean NAW transport = 4.0 Sv (trend ~ -0.1 Sv per annum) Sherwin et al,. (2008) mean NAW transport = 3.5 Sv±0.1 Sv (2.1 Sv barotropic, 1.4 Sv baroclinic) B C D E Sv cm/s Hughes et al., (2006)

6. 0423 h 19 May 1999

7. 23 233 359 397 209 Surface drifter and ADCP EKE (cm 2 /s 2 )

8. SEASONAL VARIATION IN THE MEAN FLOW

9. 3.8 Sv 2.0 Sv 5.3 Sv Mean surface drifter velocities (6000 days of data)

10. Monthly mean velocities in the upper 500 m

11. Correlation between monthly mean transport in the upper 500 and SW wind stress from NCAR/NCEP 2.3 Sv 4.1 Sv

12. BAROCLINIC / BAROTROPIC BREAKDOWN

13. Examples of strong and weak geostrophic transport (from CTD sections) 12 September 1999, Q geo = 1.7 Sv NAW 15 June 1997, Q geo = 0.33 Sv MNAW

14. Mean and mode 1 transports across the FSC Mean Mode 1 ADCP Geostrophic

15. HOW THOR IS ADDRESSING BOTH PROBLEMS (mesoscale variability and the shelf edge)

16. In THOR we add 2 extra ADCPs

17. Trawl proof frame for shallow mooring

18. SUMMARY Contrary to earlier shorter term analysis there does appear to be a seasonal variation in the transport of NAW of ~ 1.8 Sv (± 50%) Identified some difficulties that limit the accuracy of absolute mean transport Large mesoscale variability makes it difficult to determine means and trends with this configuration After 15 years of observation it is difficult to argue for a relocation of the moorings