@article {kostov_fast_2022,
	title = {Fast mechanisms linking the Labrador Sea with subtropical Atlantic overturning},
	journal = {Climate Dynamics},
	year = {2022},
	month = {aug},
	abstract = {We use an ocean general circulation model and its adjoint to analyze the causal chain linking sea surface buoyancy anomalies in the Labrador Sea to variability in the deep branch of the Atlantic meridional overturning circulation (AMOC) on inter-annual timescales. Our study highlights the importance of the North Atlantic Current (NAC) for the north-to-south connectivity in the AMOC and for the meridional transport of Lower North Atlantic Deep Water (LNADW). We identify two mechanisms that allow the Labrador Sea to impact velocities in the LNADW layer. The first mechanism involves a passive advection of surface buoyancy anomalies from the Labrador Sea towards the eastern subpolar gyre by the background NAC. The second mechanism plays a dominant role and involves a dynamical response of the NAC to surface density anomalies originating in the Labrador Sea; the NAC adjustment modifies the northward transport of salt and heat and exerts a strong positive feedback, amplifying the upper ocean buoyancy anomalies. The two mechanisms spin up/down the subpolar gyre on a timescale of years, while boundary trapped waves rapidly communicate this signal to the subtropics and trigger an adjustment of LNADW transport on a timescale of months. The NAC and the eastern subpolar gyre play an essential role in both mechanisms linking the Labrador Sea with LNADW transport variability and the subtropical AMOC. We thus reconcile two apparently contradictory paradigms about AMOC connectivity: (1) Labrador Sea buoyancy anomalies drive AMOC variability; (2) water mass transformation is largest in the eastern subpolar gyre.},
	keywords = {AMOC, Atlantic Meridional Overturning Circulation, Labrador Sea, LNADW, Lower North Atlantic Deep Water, NAC, North Atlantic Current, OSNAP, RAPID-MOCHA, Surface heat fluxes, water mass transformation},
	issn = {1432-0894},
	doi = {10.1007/s00382-022-06459-y},
	url = {https://doi.org/10.1007/s00382-022-06459-y},
	author = {Kostov, Yavor and Messias, Marie-Jos{\'e} and Mercier, Herl{\'e} and Johnson, Helen L. and Marshall, David P.}
}
@article {RN295,
	title = {Distinct sources of interannual subtropical and subpolar Atlantic overturning variability},
	journal = {Nature Geoscience},
	volume = {14},
	number = {7},
	year = {2021},
	pages = {491-495},
	type = {Journal Article},
	doi = {10.1038/s41561-021-00759-4},
	url = {https://app.dimensions.ai/details/publication/pub.1138476478 http://nora.nerc.ac.uk/id/eprint/530907/1/Kostov_et_al_Third_Submission_NatGeo_REF.pdf},
	author = {Kostov, Yavor and Johnson, Helen L. and Marshall, David P. and Heimbach, Patrick and Forget, Gael and Holliday, N. Penny and Lozier, M. Susan and Li, Feili and Pillar, Helen R. and Smith, Timothy}
}
@article {RN299,
	title = {AMOC sensitivity to surface buoyancy fluxes: the role of air-sea feedback mechanisms},
	journal = {Climate Dynamics},
	volume = {53},
	number = {7-8},
	year = {2019},
	pages = {4521-4537},
	type = {Journal Article},
	doi = {10.1007/s00382-019-04802-4},
	url = {https://app.dimensions.ai/details/publication/pub.1115011343 https://link.springer.com/content/pdf/10.1007/s00382-019-04802-4.pdf},
	author = {Kostov, Yavor and Johnson, Helen L. and Marshall, David P.}
}
@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.}
}
