@article {evans_mixing_2023,
	title = {Mixing and air{\textendash}sea buoyancy fluxes set the time-mean overturning circulation in the subpolar North Atlantic and Nordic Seas},
	journal = {Ocean Science},
	volume = {19},
	number = {3},
	year = {2023},
	note = {Publisher: Copernicus GmbH},
	pages = {745{\textendash}768},
	abstract = {The overturning streamfunction as measured at the OSNAP (Overturning in the Subpolar North Atlantic Program) mooring array represents the transformation of warm, salty Atlantic Water into cold, fresh North Atlantic Deep Water (NADW). The magnitude of the overturning at the OSNAP array can therefore be linked to the transformation by air{\textendash}sea buoyancy fluxes and mixing in the region north of the OSNAP array. Here, we estimate these water mass transformations using observational-based, reanalysis-based and model-based datasets. Our results highlight that air{\textendash}sea fluxes alone cannot account for the time-mean magnitude of the overturning at OSNAP, and therefore a residual mixing-driven transformation is required to explain the difference. A cooling by air{\textendash}sea heat fluxes and a mixing-driven freshening in the Nordic Seas, Iceland Basin and Irminger Sea precondition the warm, salty Atlantic Water, forming subpolar mode water classes in the subpolar North Atlantic. Mixing in the interior of the Nordic Seas, over the Greenland{\textendash}Scotland Ridge and along the boundaries of the Irminger Sea and Iceland Basin drive a water mass transformation that leads to the convergence of volume in the water mass classes associated with NADW. Air{\textendash}sea buoyancy fluxes and mixing therefore play key and complementary roles in setting the magnitude of the overturning within the subpolar North Atlantic and Nordic Seas. This study highlights that, for ocean and climate models to realistically simulate the overturning circulation in the North Atlantic, the small-scale processes that lead to the mixing-driven formation of NADW must be adequately represented within the model{\textquoteright}s parameterisation scheme.},
	keywords = {14 Life Below Water},
	issn = {1812-0784},
	doi = {10.5194/os-19-745-2023},
	url = {https://os.copernicus.org/articles/19/745/2023/},
	author = {Evans, Dafydd Gwyn and Holliday, N. Penny and Bacon, Sheldon and Le Bras, Isabela}
}
@article {chafik_observed_2023,
	title = {Observed mechanisms activating the recent subpolar North Atlantic Warming since 2016},
	journal = {Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences},
	volume = {381},
	number = {2262},
	year = {2023},
	note = {Publisher: Royal Society},
	month = {oct},
	pages = {20220183},
	abstract = {The overturning circulation of the subpolar North Atlantic (SPNA) plays a fundamental role in Earth{\textquoteright}s climate variability and change. Here, we show from observations that the recent warming period since about 2016 in the eastern SPNA involves increased western boundary density at the intergyre boundary, likely due to enhanced buoyancy forcing as a response to the strong increase in the North Atlantic Oscillation since the early 2010s. As these deep positive density anomalies spread southward along the western boundary, they enhance the North Atlantic Current and associated meridional heat transport at the intergyre region, leading to increased influx of subtropical heat into the eastern SPNA. Based on the timing of this chain of events, we conclude that this recent warming phase since about 2016 is primarily associated with this observed mechanism of changes in deep western boundary density, an essential element in these interactions. This article is part of a discussion meeting issue {\textquoteleft}Atlantic overturning: new observations and challenges{\textquoteright}.},
	keywords = {Atlantic Meridional Overturning Circulation},
	doi = {10.1098/rsta.2022.0183},
	url = {https://royalsocietypublishing.org/doi/10.1098/rsta.2022.0183},
	author = {Chafik, L{\'e}on and Penny Holliday, N. and Bacon, Sheldon and Baker, Jonathan A. and Desbruy{\`e}res, Damien and Frajka-Williams, Eleanor and Jackson, Laura C.}
}
@article {RN298,
	title = {Atlantic Meridional Overturning Circulation: Observed Transport and Variability},
	journal = {Frontiers in Marine Science},
	volume = {6},
	year = {2019},
	pages = {260},
	type = {Journal Article},
	doi = {10.3389/fmars.2019.00260},
	url = {https://app.dimensions.ai/details/publication/pub.1116893735 https://www.frontiersin.org/articles/10.3389/fmars.2019.00260/pdf},
	author = {Frajka-Williams, Eleanor and Ansorge, Isabelle J. and Baehr, Johanna and Bryden, Harry L. and Chidichimo, Maria Paz and Cunningham, Stuart A. and Danabasoglu, Gokhan and Dong, Shenfu and Donohue, Kathleen A. and Elipot, Shane and Heimbach, Patrick and Holliday, N. Penny and Hummels, Rebecca and Jackson, Laura C. and Karstensen, Johannes and Lankhorst, Matthias and Le Bras, Isabela A. and Lozier, M. Susan and McDonagh, Elaine L. and Meinen, Christopher S. and Mercier, Herl{\'e} and Moat, Bengamin I. and Perez, Renellys C. and Piecuch, Christopher G. and Rhein, Monika and Srokosz, Meric A. and Trenberth, Kevin E. and Bacon, Sheldon and Forget, Gael and Goni, Gustavo and Kieke, Dagmar and Koelling, Jannes and Lamont, Tarron and McCarthy, Gerard D. and Mertens, Christian and Send, Uwe and Smeed, David A. and Speich, Sabrina and van den Berg, Marcel and Volkov, Denis and Wilson, Chris}
}
@article {RN24,
	title = {Overturning in the Subpolar North Atlantic Program: A New International Ocean Observing System},
	journal = {Bulletin of the American Meteorological Society},
	volume = {98},
	number = {4},
	year = {2017},
	pages = {737-752},
	type = {Journal Article},
	abstract = {For decades oceanographers have understood the Atlantic meridional overturning circulation (AMOC) to be primarily driven by changes in the production of deep-water formation in the subpolar and subarctic North Atlantic. Indeed, current Intergovernmental Panel on Climate Change (IPCC) projections of an AMOC slowdown in the twenty-first century based on climate models are attributed to the inhibition of deep convection in the North Atlantic. However, observational evidence for this linkage has been elusive: there has been no clear demonstration of AMOC variability in response to changes in deep-water formation. The motivation for understanding this linkage is compelling, since the overturning circulation has been shown to sequester heat and anthropogenic carbon in the deep ocean. Furthermore, AMOC variability is expected to impact this sequestration as well as have consequences for regional and global climates through its effect on the poleward transport of warm water. Motivated by the need for a mechanistic understanding of the AMOC, an international community has assembled an observing system, Overturning in the Subpolar North Atlantic Program (OSNAP), to provide a continuous record of the transbasin fluxes of heat, mass, and freshwater, and to link that record to convective activity and water mass transformation at high latitudes. OSNAP, in conjunction with the Rapid Climate Change{\textendash}Meridional Overturning Circulation and Heatflux Array (RAPID{\textendash}MOCHA) at 26{\textdegree}N and other observational elements, will provide a comprehensive measure of the three-dimensional AMOC and an understanding of what drives its variability. The OSNAP observing system was fully deployed in the summer of 2014, and the first OSNAP data products are expected in the fall of 2017.},
	issn = {0003-0007 1520-0477},
	doi = {10.1175/bams-d-16-0057.1},
	url = {https://staging-ddpp.dimensions.ai/details/publication/pub.1038223668 http://darchive.mblwhoilibrary.org/bitstream/1912/9015/1/bams-d-16-0057.1.pdf},
	author = {Susan Lozier, M. and Bacon, Sheldon and Bower, Amy S. and Cunningham, Stuart A. and Femke de Jong, M. and de Steur, Laura and deYoung, Brad and Fischer, J{\"u}rgen and Gary, Stefan F. and Greenan, Blair J. W. and Heimbach, Patrick and Holliday, Naomi P. and Houpert, Lo{\"\i}c and Inall, Mark E. and Johns, William E. and Johnson, Helen L. and Karstensen, Johannes and Li, Feili and Lin, Xiaopei and Mackay, Neill and Marshall, David P. and Mercier, Herl{\'e} and Myers, Paul G. and Pickart, Robert S. and Pillar, Helen R. and Straneo, Fiammetta and Thierry, Virginie and Weller, Robert A. and Williams, Richard G. and Wilson, Chris and Yang, Jiayan and Zhao, Jian and Zika, Jan D.}
}
