image:AGU 2003 Steingrímur Jónsson, University of Akureyri & Marine Research Institute Héðinn Valdimarsson, Marine Research Institute, Reykjavik Bogi Hansen, Faroe Marine Research Institute, Tórshavn Karin Margretha H. Larsen, Faroe Marine Research Institute, Tórshavn Barbara Berx, Marine Scotland Science, Marine Laboratory, Aberdeen Toby Sherwin, SAMS, Scottish Marine Institute, Oban Steffen M. Olsen, Danish Meteorological Institute, Copenhagen Kerstin Jochumsen, Institut für Meereskunde, Universität Hamburg Detlef Quadfasel, Institut für Meereskunde, Universität Hamburg Svein Østerhus, Uni Research, Bergen from space by winds by ocean currents Heat Mass and heat exchanges across the Greenland Scotland Ridge and the AMEX budget balance Trieste 10 Oct. 2013

Denmark Strait Hudson Strait FSC IFR English Channel Arctic Mediterranean Exchanges AMEX

AGU, 2003 Transport (mass and heat) observatories 1995-ongoing From Bogi’s presentation at the kick-off NACLIM

Tools Current meters (ADCP) Hydrography CTD-sections

AGU, 2003 image:AGU 2003 Atlantic inflow volume transport No trend !!!!!!!!!!!!!!!!!!!!!!!!! Iceland branch Inflowing Atlantic water (millions m 3 /second) Faroe branch No weakening Shetland branch No trend

image:AGU 2003 Iceland branch Inflowing Atlantic water (millions m 3 /second) Faroe branch Shetland branch Atlantic inflow volume transport Atlantic inflow volume transport

Total Atlantic Volume Inflow Sv +- 1 Sv 8.5 Sv (Østerhus et al. 2005) New results Hansen et al. 2010, Jonsson and Valdimarsson 2012, Berx et al Sv

Berx, Hansen, Østerhus, K. M. Larsen, T. Sherwin, and K. Jochumsen, (2013). Combining in-situ measurements and altimetry to estimate volume, heat and salt transport variability through the Faroe Shetland Channel

Monthly mean net inflow from observations (FSC+IF+DS) and overflow (FBC+DS). Only months where all three (two) inflow (overflow) have been monitored are included. The net exchange is defined where both inflow and overflow are monitored. Return flow / overflow

Volume budget ”Old numbers” ( 1 Sv = 10 6 m 3 /s ) Q = 8.5 Sv (Østerhus et al. 2005) 6 Sv 2.5 Sv

Volume budget ”New numbers” ( 1 Sv = 10 6 m 3 /s ) Q = Sv 6 -? Sv 2.5 -? Sv assumption: Bering Strait inflow ~ West of Greenland outflow. English Channel ~ NaN

Denmark Strait Hudson Strait FSC IFR English Channel Arctic Mediterranean Exchanges

AMEX Budget GapBranchSvReferance Greenland Scotland RidgeAtlantic Inflow DS0,90Jonsson & Valdimarson Atlantic Inflow IFR3,50Hansen et al. Atlantic Inflow FSC2,70Berx et al 2013 Orkney–Shetland inflow0,30Otto et al. (1990) Surface outflow EGC-0,50Balance DS_Overflow-3,00Jochumsen et al IF_Overflow-0,70Beaird et al FBC_Overflow-2,10Hansen & Østerhus 2007 WTR_Overflow-0,20Sherwin et al. English ChannelInflow0,10Prandle et al. (1996) Bering Strait2001= =1.11,10Woodgate et al., 2012 David Strait ,30Curry et al. (2011) Rivers + E-P 0,20Ref? Balance 0,00 ?

Heat Transport Cooling: ΔT Heat import = c · Q · ΔT≈ c · Q · T Volume transport: Q Temperature: T

Shetland branch Faroe branch Iceland branch Atlantic inflow temperature 1950 – 2010 Heat import = c · Q · T

Temperature in Atlantic layer at station M Monthly mean Yearly mean

The effect of SPG shrinkage (Hakkinen & Rhines, 2004; Hátún et al., 2005) Warmer and more saline Before 1995After 1995

Observed and simulated gyre index (SSH averaged for 60°W–15°W, 48°N–65°N) Lohman et al. (2009) WeakStrong

Weak and Strong Gyre index Lohman et al. (2009) WeakStrong Atlantic Water Temperature in the Nordic Seas (M)

Denmark Strait Hudson Strait FSC IFR English Channel Arctic Mediterranean Exchanges

Next Including time series from Bering and David straits Combining observation and model results Closing the AMEX budget on down to seasonal / monthly time scale

Intensity and seasonality of the ocean exchange system with the Arctic Mediterranean west (a) and east (b) of Greenland. Stacked, monthly averaged contributions from individual inflow (bottom) and outflow (top) branches are shown including in a) the English Channel (EC) light inflow (grey), Faroe Shetland Channel (FSC) Atlantic inflow (red) and dense, deep outflow (red), the Denmark Strait (DS) Atlantic inflow (green) and dense outflow (green) and the East Greenland Current (EGC) polar water outflow (blue). The net exchange is shown in black (positive for net inflow). In b) the inflow includes the light inflow through Bering Strait (BS) and outflows the polar water in Lancaster Sound (LS) and Nares Strait (NS).

Variability of transport estimates of inflow, overflow and outflow from the global model east of Greenland compared against observations. Model values have been bias corrected and only months where observational data exists are included in the annual means Model (bias)ObservedModel East of Greenland FSC inflow2.65 (+0.05)2.71 IF inflow3.88 (-0.34) DS inflow0.73 (+0.1) EC inflow 0.08 FSC overflow1.73 (+0.41) IF overflow 0.00 DS overflow2.41 (+0.96) EGC outflow 3.35 Total in/out 7.35/7.44 West of Greenland BS inflow 1.03 NS outflow 0.93 LS outflow 0.24 Total in/out 1.03/1.17 Comparison of modeled and observed exchanges for the individual period of observations. For reference, the model average budget is included for the complete

Seasonality and characteristics of observed (black) and modeled (red) exchanges across the GSR. Seasonality (curves) is calculated as the average of monthly composites from available data in the period 1992 to 2012 and for the full model series (dashed). Variability of de-seasoned and de-trended data is illustrated by their distribution.

The research leading to these results has received funding from the European Union 7th Framework Programme (FP ), under grant agreement n NACLIM