is the oceanic heat transport with atlantic water towards the arctic changing?

image:AGU 2003

Steingrímur Jónsson, University of Akureyri & Marine Research InstituteHéðinn Valdimarsson, Marine Research Institute, ReykjavikBogi Hansen, Faroe Marine Research Institute, TórshavnKarin Margretha H. Larsen, Faroe Marine Research Institute, TórshavnBarbara Berx, Marine Scotland Science, Marine Laboratory, AberdeenToby Sherwin, SAMS, Scottish Marine Institute, ObanSteffen M. Olsen, Danish Meteorological Institute , CopenhagenKerstin Jochumsen, Institut für Meereskunde, Universität HamburgSvein Østerhus, Uni Research, Bergen

from space

by winds

by ocean currents

Heat

Is the oceanic heat transport with Atlantic water

towards the Arctic changing?

IAPSO 2013 P10S2.01

Transport (mass and heat) observatories

1995-ongoing

10 km

0

100

200

300

400

500

600

700

800

900

Dep

th(m

)

FaroeP lateau

FaroeBank

3°C2°C

1°C

<0°C

6°C

7°C<8°C

>8°C

<-0.5°C>1.1 m/s 1 m/s

0.9 m/s

0.4 m/s

0.2m

/s

FC FB FA

Atla nticWa te r

Fa ro e Ba nk C ha nne l

Fa roeBa nk

Fa roePla te a u

10 km

NACLIM

Tools

Current meters (ADCP)Current meters (ADCP)Hydrography CTD-sectionsHydrography CTD-sections

image:AGU 2003

Atlantic inflow volume transport

No trend !!!!!!!!!!!!!!!!!!!!!!!!!

Icelandbranch

Inflowing Atlantic water (millions m3/second)

Faroebranch

No weakening

Shetlandbranch

No trend

image:AGU 2003

Icelandbranch

Inflowing Atlantic water (millions m3/second)

Faroebranch Shetland

branch

Atlantic inflow volume transportAtlantic inflow volume transport

Total Atlantic Volume Inflow1997-2011

7.0 Sv+- 1 Sv+- 1 Sv

8.5 Sv (Østerhus et al. 2005)

New results

Hansen et al. 2010, Jonsson and Valdimarsson 2012, Berx et al. 2013

0.7 Sv0.7 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

Volume budget”Old numbers”

( 1 Sv = 106 m3/s )

Q = 8.5 Sv (Østerhus et al. 2005)

6 Sv

2.5 Sv

Volume budget”New numbers”

( 1 Sv = 106 m3/s )

Q = 7.0 +- Sv

6 -? Sv

2.5 -? Sv

assumption: Bering Strait inflow ~ West of Greenland outflow. English Channel ~ NaN

Heat Transport

Cooling: ΔT

Heat import = c · Q · ΔT ≈ c · Q · T

Volumetransport: Q

Temperature: T

Shetland branch

Faroe branch

Iceland branch

Atlantic inflow temperature 1950 – 2010

Heat import = c · Q · T

Temperature changes from Rockall to Fram Strait

1950-2008

Holliday et al. GRL (2008)

Tem

pera

ture

ano

mal

y 0-

500

m C

Temperature in Atlantic layer at station M1948-2010

Monthly mean

Yearlymean

The effect of SPG shrinkage(Hakkinen & Rhines, 2004; Hátún et al., 2005)

Warmer and more saline

Before 1995After 1995

3.0

1.5

0

-1.5

-3.0

Observed and simulated gyre index(SSH averaged for 60°W–15°W, 48°N–65°N)

Lohman et al. (2009)

Weak

Strong

3.0

1.5

0

-1.5

-3.0

Weak and Strong Gyre index

Lohman et al. (2009)

Weak

Strong

Atlantic Water Temperature in the Nordic Seas (M)

Conclusions:Conclusions:

There is no indication for a change There is no indication for a change in the volume transport,1997-2011 in the volume transport,1997-2011

But there is an indication that the But there is an indication that the oceanic heat (and salt) transport oceanic heat (and salt) transport towards the European Arctic has towards the European Arctic has

increased since 1995 due to increased since 1995 due to increased water temperatureincreased water temperature

but!but!

Confused?Confused?

Please ask! Please ask! www.naclim.eu

www.folk.uib.no/ngfsoSvein ØsterhusSvein Østerhus

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