The Faroe Current: T-S properties and volume, heat and salt transports Karin Margretha H. Larsen Bogi Hansen, Hjálmar Hátún, Svein Østerhus Extended Ellett Line Workshop, Apr 2015

North Atlantic Gyres SPG STG EEL Faroes

Faroese Standard Sections N V E S The Faroe Current

Atlantic Water properties Rockall Trough - From ICES IROC Warming due to Subpolar Gyre changes (Hátún et al, 2005) Modulation by air-sea heatflux variability (Larsen et al, 2012)

Atlantic Water properties Increasing salinity due to Subpolar Gyre changes Salinity variability due to changes in source water properties

Modifications in the Faroe area T W, S W T N, S N Cooling/ freshening

The salinity difference and Faroe Current volume transports Low volume transports increase the residence time: - Increased amospheric influence - Increased admixture Low volume transports increase the residence time: - Increased amospheric influence - Increased admixture SS Vol. tr

Atlantic water on monitoring section ADCPs: Atlantic Arctic

Sea level difference across the flow Satellite altimetry Weekly averaged volume transport based on in-situ observations Hansen et al, Ocean Science

Combining altimetry and in-situ obs. 1. Velocity field using long-term ADCP and CTD records to calibrate altimetry, we can generate daily estimates of the velocity field every day since 1 st January Temperature and salinity field altimetry + seasonal variation + long-term Atlantic water temperature and salinity to generate daily estimates of the property fields

Monthly averaged volume transport of Atlantic water Average volume transport of Atlantic water: 3.8 ± 0.5 Sv Hansen et al, Submitted to OS

AW transport Weak seasonal variation Amplitude < 10% of avg transport ± standard error 20 year trend: 9±8% (95% confidence) Annual mean 3-year mean

Heat transport relative to 0°C 20 year trend: 18±8%

20 year trend: 130±30% Salt transport relative to (≈ FBC-overflow salinity)

Conclusions Variation of AW (T,S) is dominated the Subpolar Gyre and modulated by source water variability and atmospheric heat loss variability Faroe Current volume, heat and salt transports towards the Arctic have increased in the last 20 years The research leading to these results has received funding from the European Union 7th Framework Programme (FP ), under grant agreement n NACLIM