GEOMAR 53° N Observatory

The 53°N observatory is an ocean observatory that is in operation since 1997 at the “exit” of the Labrador Sea. Dedicated ship-based and moored observations are routinely obtained to analyse characteristics and processes related to all components of the Deep Western Boundary Current (DWBC).

Specific research interest is in:

  • Observing regional flow and thermohaline variability from days to decades
  • Augmenting biogeochemistry observations to a long-term observatory (e.g., oxygen)
  • Model validation (e.g., mean vertical current structure, volume transport)
  • Contributing to international OSNAP for sustained observing of AMOC in the subpolar North Atlantic sector

Mean velocity structure

The mean velocity structure is derived from lowered ADCP velocity surveys obtained during 17 research cruises from 1997 to 2024 at the 53°N observatory. The nominal location of moored instruments is indicated by the symbols with T/(S): temperature (mostly with salinity) recorders, u/v: velocity recorder, ADCP: upward looking acoustic doppler current profiler. 

Deep Western Boundary Current Transport time series

By integrating the southward flow across the 53°N observatory (blue-shaded area in the mean section), the transport of the Deep Western Boundary Current obtained. The 5-day (tides removed) time series as well as a 2-year running mean are also shown. The period since the integration of the 53°N observatory into the OSNAP coordination program, used for estimating the strength of the Atlantic Meridional Overturning Circulation in the subpolar sector of the North Atlantic, is highlighted accordingly.

  
Maintenance cruises:

CoffeeCup Image Mapper map file M39 VAL171 M45/3 M50 M59 MSM5/2 MSM9/2 MSM12/1 M82/2 MSM21/1a THA-MSM40 https://www.geomar.de/forschen/expeditionen/detailansicht/exp/337577 MSM74 MSM94 M184 MSM129

Key Publications

Koelling, J., Atamanchuk, D., Karstensen, J., and Wallace, D. W. R. (2023) Decadal variability of oxygen uptake, export, and storage in the Labrador Sea from observations and CMIP6 models  Frontiers in Marine Sciences, 10.3389/fmars.2023.1202299

Fu, Y., Lozier, M.S., Biló, T.C. A.S. Bower, S.A. Cunningham, F. Cyr, M.F. de de Jong, B. deYoung, L. Drysdale, N. Fraser, N. Fried, H.H. Furey, G. Han, P. Handmann, N.P. Holliday, J. Holte, M.E. Inall, W.E. Johns, S. Jones, J. Karstensen, F. Li, A. Pacini, R.S. Pickart, D. Rayner, F. Straneo and I. Yashayaev (2023) Seasonality of the Meridional Overturning Circulation in the Subpolar North Atlantic, Nature Communications, doi.org/10.1038/s43247-023-00848-9.

Koelling, J., Atamanchuk, D., Karstensen, J., Handmann, P., and Wallace, D. W. R. (2022) Oxygen export to the deep ocean following Labrador Sea Water formation, Biogeosciences, 19, 437–454, doi.org/10.5194/bg-19-437-2022

Li, F., M.S. Lozier, S. Bacon, A.S. Bower, S.A. Cunningham, M.F. de Jong, B. deYoung, N. Fraser, N. Fried, G. Han, N.P. Holliday, J. Holte, L. Houpert, M.E. Inall, W.E. Johns, S. Jones, C. Johnson, J. Karstensen, I.A. Le Bras, P. Lherminier, X. Lin, H. Mercier, M. Oltmanns, A. Pacini, T. Petit, R.S. Pickart, D. Rayner, F. Straneo, V. Thierry, M. Visbeck, I. Yashayaev and C. Zhou (2021) Subpolar North Atlantic western boundary density anomalies and the Meridional Overturning Circulation. Nat Commun 12, 3002. doi.org/10.1038/s41467-021-23350-2

Biastoch, A., Schwarzkopf, F. U., Getzlaff, K., Rühs, S., Martin, T., Scheinert, M., Schulzki, T., Handmann, P., Hummels, R., and Böning, C. W. (2021) Regional imprints of changes in the Atlantic Meridional Overturning Circulation in the eddy-rich ocean model VIKING20X, Ocean Sci., 17, 1177–1211, doi.org/10.5194/os-17-1177-2021

Pacini, A., R.S. Pickart, F. Bahr, D.J. Torres, A. Ramsey, J. Holte, J. Karstensen, M. Oltmanns, F. Straneo, I.A. Le Bras, G.W.K. Moore, and M.F. de Jong, (2020). Mean conditions and seasonality of the West Greenland boundary current system Journal of Physical Oceanography, 50, 2849-2871. 10.1175/JPO-D-20-0086.1.

Frajka-Williams E, Ansorge IJ, Baehr J, Bryden HL, Chidichimo MP, Cunningham SA, Danabasoglu G, Dong S, Donohue KA, Elipot S, Heimbach P, Holliday NP, Hummels R, Jackson LC, Karstensen J, Lankhorst M, Le Bras IA, Lozier MS, McDonagh EL, Meinen CS, Mercier H, Moat BI, Perez RC, Piecuch CG, Rhein M, Srokosz MA, Trenberth KE, Bacon S, Forget G, Goni G, Kieke D, Koelling J, Lamont T, McCarthy GD, Mertens C, Send U, Smeed DA, Speich S, van den Berg M, Volkov D and Wilson C (2019) Atlantic Meridional Overturning Circulation: Observed Transport and Variability. Front. Mar. Sci. 6:260. doi: 10.3389/fmars.2019.00260

Lozier, M.S., F. Li, S. Bacon, F. Bahr, A.S. Bower, S.A. Cunningham, M.F. de Jong, L. de Steur, B. DeYoung, J. Fischer, S.F. Gary, N.J.W. Greenan, N.P. Holliday, A. Houk, L. Houpert, M.E. Inall, W.E. Johns, H.L. Johnson, C. Johnson, J. Karstensen, G. Koman, I.A. LeBras, X. Lin, N. Mackay, D.P. Marshall, H. Mercier, M. Oltmanns, R.S. Pickart, A.L. Ramsey, D. Rayner, F. Straneo, V. Thierry, D.J. Torres, R.G. Williams, C. Wilson, J. Yang, I. Yashayaev and J. Zhao, (2019) A Sea Change in Our View of Overturning – First Results from the Overturning in the Subpolar North Atlantic Program, Science, 363, 516–521, February 1, doi: 10.1126/science.aau6592.

Fischer, J., Karstensen, J., Oltmanns, M., and Schmidtko, S. (2018) Mean circulation and EKE distribution in the Labrador Sea Water level of the subpolar North Atlantic, Ocean Sci., 14, 1167-1183, doi.org/10.5194/os-14-1167-2018

Holliday, N. P., Bacon, S., Cunningham, S. A., Gary, S. F., Karstensen, J., King, B. A., Li, F., & McDonagh, E. L. (2018), Subpolar North Atlantic Overturning and gyre-scale circulation in the summer 2014 and 2016. Journal of Geophysical Research: Oceans, 122. doi.org/10.1029/2018JC013841

Handmann, P., Fischer, J., Visbeck, M., Karstensen, J., Biastoch, A., Böning, C., & Patara, L. The deep western boundary current in the Labrador Sea from observations and a high-resolution model. (2018) Journal of Geophysical Research: Oceans, 123, 2829-2850. doi.org/10.1002/2017JC013702

Zantopp, R., J. Fischer, M. Visbeck, and J. Karstensen (2017), From interannual to decadal: 17 years of boundary current transports at the exit of the Labrador Sea, J. Geophys. Res. Oceans, 122, doi:10.1002/2016JC012271

Lozier, S., S. Bacon, A.S. Bower, S.A. Cunningham, M.M. Femke de Jong, L. de Steur, B. deYoung, J. Fischer, S.F. Gary, B.W. Greenan, P. Heimbach, N.P. Holliday, L. Houpert, M.E. Inall, W.E. Johns, H.L. Johnson, J. Karstensen, F. Li, X. Lin, N. Mackay, D.P. Marshall, H. Mercier, P.G. Myers, R.S. Pickart, H.R. Pillar, F. Straneo, V. Thierry, R.A. Weller, R.G. Williams, C. Wilson, J. Yang, J. Zhao, and J.D. Zika (2017), Overturning in the Subpolar North Atlantic Program: A New International Ocean Observing System. Bull. Amer. Meteor. Soc., 98, 737–752, doi: 10.1175/BAMS-D-16-0057.1.

Fischer, J., Karstensen, J., Zantopp, R. J., Visbeck, M., Biastoch, A., Behrens, E., Böning, C. W., Quadfasel, D., Jochumsen, K., Valdimarsson, H., Jónsson, S., Bacon, S., Holliday, N. P., Dye, S., Rhein, M. and Mertens, C. (2015), Intra-seasonal variability of the DWBC in the western subpolar North Atlantic, Progress in Oceanography, 132, 233-249, DOI 10.1016/j.pocean.2014.04.002

Han, G., N. Chen, and Z. Ma (2014), Is there a north-south phase shift in the surface Labrador Current on the interannual-to-decadal scale?, J. Geophys. Res. Oceans, 119, 276–287, doi:10.1002/2013JC009102.

Xu, X., Hurlburt, H. E., Schmitz, W. J., Zantopp, R. J., Fischer, J. und Hogan, P. J., (2013), On the currents and transports connected with the atlantic meridional overturning circulation in the subpolar North Atlantic Journal of Geophysical Research - Oceans, 118 (1). pp. 502-516. DOI 10.1002/jgrc.20065.

Fischer, J., M. Visbeck, R. Zantopp, und N. Nunes (2010), Interannual to decadal variability of outflow from the Labrador Sea, Geophys. Res. Lett., 37, doi:10.1029/2010GL045321.

Böning, C. W., M. Scheinert, J. Dengg, A. Biastoch, and A. Funk (2006), Decadal variability of subpolar gyre transport and its reverberation in the North Atlantic overturning, Geophys. Res. Lett., 33, L21S01, doi:10.1029/2006GL026906.

Dengler, M., J. Fischer, F. A. Schott, und R. Zantopp (2006). Deep Labrador Current and its variability in 1996–2005, Geophys. Res. Lett., 33, L21S06, doi:10.1029/2006GL026702.

Schott, F. A., J. Fischer, M. Dengler, und R. Zantopp (2006) Variability of the Deep Western Boundary Current east of the Grand Banks, Geophys. Res. Lett., 33, L21S07, doi:10.1029/2006GL026563.

Schott, F. A., J. Fischer, R. Zantopp, M. Dengler, L. Stramma, und M. Wibaux, (2004) Currents and transports at the western exit of the subpolar North Atlantic J. Phys. Oceanogr., 34, 817-843.

Fischer, J. und F. A. Schott, und M. Dengler (2004): Boundary circulation at the exit of the Labrador Sea. J. Phys. Oceanogr., 34 , 1548-1570

Stramma, L., Kieke, D., Rhein, M., Schott, F., Yashayaev, I., and Koltermann, K.P. (2004), Deep water changes at the western boundary of the subpolar North Atlantic during 1996 to 2001, Deep Sea Research Part I: Oceanographic Research Papers Vol. 51, No. 8, pp 1033, 09670637.