OCEANIC CONVECTION AND STRATIFICATION IN THE NORTHERN ATLANTIC AS OB SERVED IN WINTER 2013/14
Abstract
Spatial characteristics of oceanic convection in the North Atlantic Subpolar Gyre in winter 2013/14 are investigated basing on the analysis of Argo float data. Domains of the most intense convective mixing are identified by quantifying and mapping the water column vertical stratification. The areas of the Subpolar Mode Water formation are found along the Irminger Current, namely over the northwestern slope of the Reykjanes Ridge and in the vicinity of the Denmark Strait. The location of convection domains and the spatial changes of mixed layer properties in these domains are in a good agreement with a contemporary concept stating the localized formation of the mode waters along each of the individual branches of the North Atlantic Current and the increasing density of the mode waters in the northward direction. The main role in the formation of the Labrador Sea Water belonged to the convection zone in the Labrador Sea, where the mixing depth reached 1750 m for the first time over the past six years. The relatively cold and fresh intermediate waters, matching the Labrador Sea Water in their properties, were also formed in the domain to the south of the Cape Farewell and in the southern part of the Irminger Sea.
About the Authors
A. S. Falina
Shirshov Institute of Oceanology of the Russian Academy of Sciences.
Russian Federation
Laboratory of Hydrological Processes, Senior Research Scientist, PhD in Geography.
Russian Federation
Laboratory of Hydrological Processes, Senior Research Scientist, PhD in Geography.
A. A. Sarafanov
Shirshov Institute of Oceanology of the Russian Academy of Sciences.
Russian Federation
Laboratory of Hydrological Processes, Senior Research Scientist, D.Sc. in Geography.
Russian Federation
Laboratory of Hydrological Processes, Senior Research Scientist, D.Sc. in Geography.
S. A. Dobrolyubov
Lomonosov Moscow State University.
Russian Federation
Faculty of Geography, Dean of the Faculty, Professor, D.Sc. in Geography.
Russian Federation
Faculty of Geography, Dean of the Faculty, Professor, D.Sc. in Geography.
V. S. Zapotylko
Shirshov Institute of Oceanology of the Russian Academy of Sciences.
Russian Federation
Department of Scientific Expeditions and Fleet, main expert.
Russian Federation
Department of Scientific Expeditions and Fleet, main expert.
S. V. Gladyshev
Shirshov Institute of Oceanology of the Russian Academy of Sciences
Russian Federation
Department of Scientific Expeditions and Fleet, Deputy Head of the Department.
Russian Federation
Department of Scientific Expeditions and Fleet, Deputy Head of the Department.
References
1. Avsic T., Karstensen J., Send U, Fischer J. Interannual variability of newly formed Labrador Sea Water from 1994 to 2005 / / Geophys. Res. Lett. 2006. V. 33. L21S02; doi:10.1029/2006gl026913,2006.
2. Bersch M., Meincke J., Sy A. Interannual thermohaline changes in the northern North Atlantic 1991–1996 // Deep-Sea Res. Part II. 1999. V. 46. P. 55–75.
3. Brambilla E., Talley L.D. Subpolar Mode Water in the northeastern North Atlantic: 1. Averaged properties and mean circulation // J. Geophys. Res. 2008. V. 113. C04025; doi:10.1029/ 2006JC004062.
4. de Boisseson E., Thierry V., Mercier H., Caniaux G., Desbruyиres D. Origin, formation and variability of the Subpolar Mode Water located over the Reykjanes Ridge // J. Geophys. Res. 2012. V. 117. C12005; doi:10.1029/2011JC007519.
5. de Boyer Montegut C., Madec G., Fischer A.S., Lazar A., Iudicone D. Mixed layer depth over the global ocean: an examination of profile data and a profile-based climatology // J. Geophys. Res. 2004. V. 109. C12003; doi:10.1029/2004JC002378.
6. de Jong M.F., van Aken H.M., Vage K., Pickart R.S. Convective mixing in the central Irminger Sea: 2002–2010 // Deep-Sea Res. 2012. V. 63. P. 36–51; doi:10.1016/j.dsr.2012.01.003.
7. Dobrolyubov S.A., Sokov A.V. Rol glubinnyh vod Severnoy Atlantiki v izmenchivosti teploobmena okeana i atmosferyi [Role of the North Atlantic Deep Water in the ocean-atmosphere heat exchange] // Vestnik Moskovskogo Universiteta. Ser. Geografia. 2002. № 6. P. 42–48 (in Russian).
8. Falina A., Sarafanov A., Sokov A. Variability and renewal of Labrador Sea Water in the Irminger Basin in 1991–2004 // J. Geophys. Res. 2007. V. 112. C01006; doi:10.1029/2005JC003348.
9. Garcia-Ibanez M.I., Pardo P.C., Carracedo L.I., Mercier H., Lherminier P., Rios A.F., Perez F.F. Structure, transports and transformations of the water masses in the Atlantic Subpolar Gyre // Progr. Oceanogr. 2015. V. 135. P. 18–36.
10. Hanawa K., Talley L.D. Mode waters. in: Ocean Circulation and Climate, Int. Geophys. Ser. (edited by G. Siedler, J. Church, and J. Gould). New York, Academic. 2001. V. 77. P. 373–386.
11. Johnson G.C., Gruber N. Decadal water mass variations along 20°W in the northeastern Atlantic Ocean // Progr. Oceanogr. 2007; doi:10.1016/j.pocean.2006.03.022.
12. Kieke D., Yashayaev I. Studies of Labrador Sea Water formation and variability in the subpolar North Atlantic in the light of international partnership and collaboration // Prog. Oceanogr. 2015; http://dx.doi.org/10.1016/j.pocean.2014.12.010.
13. Lacan F., Jeandel C. Subpolar Mode Water formation traced by neodymium isotopic composition // Geophys. Res. Lett. 2004. V. 31. L14306; doi:10.1029/2004GL019747.
14. Lappo S.S. K voprosu o prichinah advekcii tepla na sever cherez ekvator v Atlanticheskom okeane [On the reasons of the northward heat advection across equator in the Atlantic Ocean]. In: Issledovanie processov vzaimodeystviya okeana i atmosphery. M., 1984. P. 125–129 (in Russian).
15. Lazier J. The renewal of Labrador Sea water // Deep-Sea Res. 1973. V. 20. P. 341–353.
16. Lazier J., Hendry R., Clarke A., Yashayaev I., Rhines P. Convection and restratification in the Labrador Sea, 1990–2000 // Deep-Sea Res. 2002. V. 49. P. 1819–1835.
17. Lilly J.M., Rhines P.B., Visbeck M., Davis R., Lazier J.R.N., Schott F., Farmer D. Observing deep convection in the Labrador Sea during winter 1994/95 // J. Phys. Oceanogr. 1999. V. 29. P. 2065– 2098.
18. McCartney M.S., Talley L.D. The Subpolar Mode Water in the North Atlantic // J. Phys. Oceanogr. 1982. V. 12. P. 1169–1188.
19. McCartney M.S., Talley L.D. Warm-to-cold water conversation in the northern North Atlantic ocean // J. Phys. Oceanogr. 1984. V. 14. P. 922–935.
20. Pickart R.S., Straneo F., Moore G.W.K. Is Labrador Sea Water formed in the Irminger basin? // Deep-Sea Res. 2003. V. 50. P. 23– 52.
21. Pickart R.S., Torres D.J., Clarke R.A. Hydrography of the Labrador Sea during active convection // J. Phys. Oceanogr. 2002. V. 32. № 3. P. 428–457.
22. Sarafanov A., Falina A., Mercier H., Sokov A., Lherminier P., Gourcuff C., Gladyshev S., Gaillard F., Daniault N. Mean full-depth summer circulation and transports at the northern periphery of theAtlantic Ocean in the 2000 s // J. Geophys. Res. 2012. V. 117. C01014; doi:10.1029/2011JC007572.
23. Thierry V., de Boissseson E., Mercier H. Interannual variability of the Subpolar Mode Water properties over the Reykjanes Ridge // J. Geophys. Res. 2008. V. 113. C04016; doi:10.1029/2007JC004443.
24. Vage K., Pickart R.S., Moore G.W.K., Ribergaard M.H. Winter Mixed Layer Development in the Central Irminger Sea: The Effect of Strong, Intermittent Wind Events // J. Phys. Oceanogr. 2008. V. 38. № 3. P. 541–565; doi: 10.1175/2007JPO3678.1.
25. Vage K., Pickart R.S., Thierry V., Reverdin G., Lee C.M., Petrie B., Agnew T.A., Wong A., Ribergaard M.H. Surprising return of deep convection to the subpolar North Atlantic Ocean in winter 2007–2008 // Nature Geoscience. 2009. V. 2. P. 67–72; doi:10.1038/NGEO382.
26. Yashayaev I., Loder J.W. Enhanced production of Labrador Sea water in 2008 // Geophys. Res. Lett. 2009. V. 36, L01606; doi:10.1029/2008GL036162.
27. Yashayaev I. Hydrographic changes in the Labrador Sea, 1960– 2005 // Prog. Oceanogr. 2007. V. 73. P. 242–276.
Review
For citations:
Falina A.S., Sarafanov A.A., Dobrolyubov S.A., Zapotylko V.S., Gladyshev S.V. OCEANIC CONVECTION AND STRATIFICATION IN THE NORTHERN ATLANTIC AS OB SERVED IN WINTER 2013/14. Vestnik Moskovskogo universiteta. Seriya 5, Geografiya. 2017;(4):45-54. (In Russ.)
Views:
770
Email this article 
