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Observed and simulated variability of the North Atlantic subpolar gyre Helge Drange & Co G. C. Rieber Climate Institute, the Nansen Center, Bergen, Norway.

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Presentation on theme: "Observed and simulated variability of the North Atlantic subpolar gyre Helge Drange & Co G. C. Rieber Climate Institute, the Nansen Center, Bergen, Norway."— Presentation transcript:

1 Observed and simulated variability of the North Atlantic subpolar gyre Helge Drange & Co G. C. Rieber Climate Institute, the Nansen Center, Bergen, Norway Bjerknes Centre for Climate Research, Bergen, Norway Geophysical Institute, University of Bergen, Norway Nansen-Zhu International Research Centre, Beijing, China

2 NOClim-cited: Curry & Mauritzen (2005); Hatun et al. (2005) NOClim-relevant: Orvik and Skagseth (2005); Mauritzen et al. (2006); Siegismund et al. (2006)

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6 Essentially Curry & Mauritzen, Science, 2005

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9 ~ hydrogrphic profiles (NISE)

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13 Orvik, Kjell Arild; Skagseth, Øystein (2005), Heat flux variations in the eastern Norwegian Atlantic Current toward the Arctic from moored instruments, 1995–2005. Geoph. Res. Lett., 32, No. 14, L /2005GL023487

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15 “...The extreme temperature increase of 1 o C appears, however, to be independent of the current strength. A future challenge here will be to reveal the cause of this extraordinary warming...”

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17 R I F

18 Altimetry MICOM SSH EOF I I F FR R The subpolar gyre influence (H ä kkinen and Rhines, Science, 2004)

19 R I A longer term perspective

20 Observed and simulated salinity anomalies from about 1970 to present Observed Simulated Irminger (I) Faroe (F) Rockall (R)

21 (inverted) WNAW ENAW FreshSaline The gyre shape and the Rockall Trough

22 Important: Relationship valid for temperature also!

23 EOF1 Wind stress curl (26%)EOF1 Buoyancy flux (19%) Red: SSH PC1 Black: SLP PC1 Green: PC1 Wind stress Blue: PC1 Buoyancy flux

24 Volume of LSW in layers 15 and 16 and the GI

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31 The dynamics of the N-Atl subpolar gyre is of key importance for the poleward transport of heat and salt The dynamics of the N-Atl subpolar gyre is largely governed by winter time bouyancy forcing Decadal-scale coupled atm-ocean mode possible - needs investigation! (coupled model system required) Current generation of OGCMs is able to complement observations NOClim has provided important insight into the variability of the (marine) climate of the N-Atl Summary:


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