Flow of Atlantic water to the North Icelandic shelf

Steingrímur Jónsson1,2

and Héðinn Valdimarsson1 1Marine Research Institute and

2University of Akureyri

28oW 26oW 24oW 22oW 20oW 18oW

16oW 65oN

30'

66oN

30'

67oN

30'

68oN

DENMARK STRAIT

ICELAND

28oW 26oW 24oW 22oW 20oW 18oW

16oW 65oN

30'

66oN

30'

67oN

30'

68oN

Kögur

Hornbanki

Si 3

10 cm/s

LB6

KG6

Map of the area. The red dots denote current meter positions and the blue denote CTD stations. Depth contours are 100, 200, 500 and 1000 meters.

Salinity on the Hornbanki section. Also shown is the position of the current meters as yellow dots.

Timeline for the measurements

HornbankiHornbanki

HB1

HB2 HB3

E-W component at the Hornbanki sectionmeasured with a vessel mounted ADCPMean from 2001-2005

Salinity on the Hornbanki section. Also shown is the position of the current meters as yellow dots.

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug

2

3

4

5

6

7

Tem

per

atu

re °

C

H1 80mH2 81mH2 151mH3 84mH3 154mVelocityH3 84m

- 2 0

0

2 0

4 0

Vel

oci

ty (

cm/s

)

Time series of temperature from the current meters. Also shown is the average of the E-W component of the velocity at mooring H3 at 84m depth (black line). Each tick on the x-axis denotes the beginning of the corresponding month. The yellow lines indicate the times when CTD sections were taken. Data are weekly running averages.

12345678910111213141516171819202122

-220 -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0

D istance (nm )

-700

-600

-500

-400

-300

-200

-100

0D

epth

(db

)

- 2

- 1

0

1

2

3

4

5

6

7

8

9

1 0

Potential temperature across the Denmark Strait at the sill, Sep. 1997.

DW

AIW

PWAW

LB6 80m

KG6 80m

HB2 80m

94 95 96 97 98 99 00 01Year

0

10

20

30

40

He

at

tra

ns

po

rt (

TW

)

0

0.5

1

1.5

Tra

ns

po

rt (

Sv

)

Transport (T)Heat transport (Q)

<T> = 0.75 Sv<Q> = 18.9 TWTransport 1999-2000

Temperature averaged from 50-100 m on the Siglunes section

0.83 Sv23 TW

3.8 Sv134 TW 3.8 Sv

156 TW

Österhus et al. (2005)

0.83 Sv = 10% of the total transport to the Nordic Seas

23 TW = 7% of the total heat transport to the Nordic Seas

Transport associated with AW

Period

Transport of AW(Sv)

Proportion of AW (%)

Heat transport

(TW)

1994-2008 0.83 67 23

1994-1995 0.50 47 12

2003 1.12 76 33

Seasonal variations in transport

Amplitude of 0.27 Sv Minimum in February/March Maximum in late spring and summer

28oW 26oW 24oW 22oW 20oW 18oW

16oW 65oN

30'

66oN

30'

67oN

30'

68oN

DENMARK STRAIT

ICELAND

28oW 26oW 24oW 22oW 20oW 18oW

16oW 65oN

30'

66oN

30'

67oN

30'

68oN

Kögur

Hornbanki

Si 3

10 cm/s

LB6

KG6

Map of the area. The red dots denote current meter positions and the blue denote CTD stations. Depth contours are 100, 200, 500 and 1000 meters.

j f m a m j j a s o n dMonth

0

0.4

0.8

1.2

Tra

ns

po

rt (

Sv

)

1994 1995 1996 1997 1998 1999 2000 2001 2002Year

-16

-12

-8

-4

0

4

8

N_S

win

d (

m/s

)

0

0.5

1

1.5

Tra

ns

po

rt (

Sv

)

TransportN-S wind

Jan-95

-180

-90

0

90

180

Deg

rees

Dec-94 Feb-95 Mar-95

-8 -4 0 4 8m/s

0

0.4

0.8

1.2

1.6

Sv

r = 0.52

Y = 0.056 * X + 0.81