1. AGU, 2003 Greenland Iceland Shet- land Faroes image:AGU 2003 Cost ‐ efficient monitoring of the main Atlantis inflow to the Arctic Mediterranean B. Hansen, K.M.H Larsen, H. Hátún, S. Østerhus Atlantic inflow Arctic Mediterranean North Atlantic Atlantic 0.9 Sv 3.5 Sv 2.7 Sv Optimizing the North Atlantic observing system

2. AGU, 2003 image:AGU 2003 Iceland Faroes Monitoring section

3. The Monitoring section through the IF-inflow Salinity Velocity (cm/s) ADCPs

4. Weekly averaged Atlantic inflow between Iceland and Faroes 1997-2013

5. Problems with the existing monitoring system Extrapolating ADCPs to surface Interpolating between ADCPs Lack of T and S data Money and effort

6. Instrumentation

7. Future monitoring system One Deepwater ADCP Two trawl- resistant Bottom Temp- erature loggers Satellite altimetry

8. Temperature from up to 95 CTD cruises Atlantic water Average 4°C isotherm ± Standard deviation Satellite altimetry ADCP Bottom temperature How much of the variance in the lower boundary of Atlantic layer can be explained by measured variables 19% 21% 15% 15% 15% 3% 3% 3% explained by ADCP 17% 34% 42% 60% 48% 30% 25% 16% explained by Altimetry 50% explained by Bottom temp. Standard CTD station Monitoring heat- and salt-, but also volume transport requires monitoring temperature and salinity Arctic water

10. Temperature sensor Acoustic modem TEmperature Longterm Logging by BOttom Grounded Instrumentation Battery capacity > 10 years NACLIM

11. The research leading to these results has received funding from the European Union 7th Framework Programme (FP7 2007-2013), under grant agreement n.308299 NACLIM www.naclim.eu