@article {srokosz_atlantic_2023,
	title = {Atlantic overturning: new observations and challenges},
	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 = {20220196},
	abstract = {This paper provides an introduction to the special issue of the Philosophical Transactions of the Royal Society of London of papers from the 2022 Royal Society meeting on {\textquoteleft}Atlantic overturning: new observations and challenges{\textquoteright}. It provides the background and rationale for the meeting, briefly summarizes prior progress on observing the Atlantic overturning circulation and draws out the new challenges that papers presented at the meeting raise, so pointing the way forward for future research. This article is part of a discussion meeting issue {\textquoteright}Atlantic overturning: new observations and challenges{\textquoteright}.},
	keywords = {AMOC, Atlantic, observations, OSNAP, overturning circulation, RAPID},
	doi = {10.1098/rsta.2022.0196},
	url = {https://royalsocietypublishing.org/doi/10.1098/rsta.2022.0196},
	author = {Srokosz, Meric A. and Holliday, N. Penny and Bryden, Harry L.}
}
@article {lozier_overturning_2023,
	title = {Overturning in the subpolar North Atlantic: a review},
	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 = {20220191},
	abstract = {The Overturning in the Subpolar North Atlantic Program (OSNAP) was initiated in the spring of 2010 through a collaborative effort involving the USA, the UK, Germany, the Netherlands and Canada. A key feature of OSNAP is a trans-basin observing system deployed in the summer of 2014 for the continuous measure of volume, heat and freshwater fluxes in the subpolar North Atlantic. This review focuses on advancements made possible by the collective OSNAP observations. Chief among those advancements is the quantification of the dominant role of the eastern subpolar North Atlantic in the production of dense waters that reside in the lower limb of the overturning: the Irminger and Iceland basins contributed approximately three times as much dense water compared with the Labrador Sea over the observational period. Other advancements include elucidation of the relationship between convective activity in the basin interior and boundary current anomalies; the spread of overflow waters in the subpolar region; the seasonality of the meridional volume, heat and freshwater fluxes; and the challenges involved in designing a simpler, less costly observing system. Collectively, OSNAP measurements are laying a framework on which to assess the overturning circulation{\textquoteright}s vulnerability to continued warming and freshening as climate change continues apace. This article is part of a discussion meeting issue {\textquoteleft}Atlantic overturning: new observations and challenges{\textquoteright}.},
	keywords = {meridional overturning circulation, OSNAP, subpolar North Atlantic},
	doi = {10.1098/rsta.2022.0191},
	url = {https://royalsocietypublishing.org/doi/10.1098/rsta.2022.0191},
	author = {Lozier, M. Susan}
}
@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 {chafik_irminger_2022,
	title = {Irminger Sea Is the Center of Action for Subpolar AMOC Variability},
	journal = {Geophysical Research Letters},
	volume = {49},
	number = {17},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022GL099133},
	pages = {e2022GL099133},
	abstract = {Significant societally important climate impacts can be caused by changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) at higher latitudes. Focusing on variability and long-term change of the subpolar North Atlantic (SPNA){\textemdash}a key AMOC action center{\textemdash}and using eastern OSNAP array observations, we identify a distinct density and sea-surface height signature of the AMOC strength in the Irminger Sea (2014{\textendash}2018), reinforced and extended with an ocean reanalysis (1993{\textendash}2018). Reconstruction of AMOC variability using Irminger Sea density shows strong control by the North Atlantic Oscillation on subpolar overturning on multiple timescales, achieved via the gyre circulation and waters from the Labrador Sea. Furthermore, the observed decrease of Irminger Sea density since the mid-twentieth century (1950{\textendash}2019) is suggestive of a long-term AMOC weakening of 2.2 Sv or 13\%, however, this trend remains statistically insignificant due to the large interannual and decadal variability of the SPNA.},
	keywords = {AMOC, OSNAP},
	issn = {1944-8007},
	doi = {10.1029/2022GL099133},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GL099133},
	author = {Chafik, L. and Holliday, N. P. and Bacon, S. and Rossby, T.}
}
@article {fraser_north_2022,
	title = {North Atlantic Current and European Slope Current Circulation in the Rockall Trough Observed Using Moorings and Gliders},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {127},
	number = {12},
	year = {2022},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022JC019291},
	pages = {e2022JC019291},
	abstract = {The Rockall Trough (RT) accommodates the warmest and saltiest branch of the North Atlantic Current, which delivers water from the Gulf Stream into the marine environment around western Europe. In addition, the European Slope Current (ESC) carries warm water northward along the eastern boundary of the RT, and exchange between the ESC and the continental shelf is a dominant factor in determining the oceanographic conditions around the British Isles. However, the picture of the mean circulation and variability in the RT is still emerging, with a continuous observational campaign still in its relative infancy. The ESC, in particular, is poorly constrained by ship-based, mooring, and satellite observations. In this paper, we examine the RT circulation and volume transport using a temporally extended and spatially expanded observing network. Six years of continuous mooring occupation reveal that a large-amplitude, basin-scale freshening event, previously detected south of Iceland around 2015, impacted the RT around 2017. Geostrophic transport was greatly reduced during this period, driven by a concurrent subsurface temperature increase at the western boundary. The circulation regained strength during the latter part of the record. We gathered 110 glider transects over 22 months which capture the ESC velocity field in unprecedented detail. The data are sufficient to characterize both the mean state and the emergent seasonal variability of the ESC, and reveal the year-round presence of a southward countercurrent at depth. Variability in the strength and structure of this previously unstudied feature modulates net northward transport in the eastern boundary current system.},
	keywords = {AMOC, Atlantic, climate, glider, OSNAP},
	issn = {2169-9291},
	doi = {10.1029/2022JC019291},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JC019291},
	author = {Fraser, Neil J. and Cunningham, Stuart A. and Drysdale, Lewis A. and Inall, Mark E. and Johnson, Clare and Jones, Sam C. and Burmeister, Kristin and Fox, Alan D. and Dumont, Estelle and Porter, Marie and Holliday, N. Penny}
}
@article {272,
	title = {The Role of the Irminger Current in the Irminger Sea Northward Transport Variability},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {127},
	year = {2022},
	month = {2022///},
	pages = {e2021JC018188},
	abstract = {The Irminger Current (IC) on the western flank of the Reykjanes Ridge is an important contributor to the northward transport in the Atlantic Meridional Overturning Circulation. Here, we combine 28 years of Copernicus Marine Environment Monitoring Service (CMEMS) ocean reanalysis data with 6 years of mooring data to investigate variability in volume transport of the IC. We found a mean volume transport for the IC of 11.6 Sv between 1993 and 2020 revealing the dominance of the IC in the total Irminger Sea northward volume transport (20.3 Sv). We found a significant decrease (-3.7 Sv) in volume transport of the IC until 2011 followed by a steeper (but shorter, leading to +2.7 Sv) increase until 2020. These changes across the Irminger Sea section are dominated by the IC, which in turn are driven by changes in the density gradient across the Irminger Sea related to convection. On decadal and interannual time scales the IC volume transport is well correlated with the decrease in the sea surface height difference over the basin. In 2019, a temporary intensification of the western IC core led to an exceptionally strong volume transport of the IC with 20 Sv. This was caused by density changes within the IC boundaries due to the presence of mesoscale eddies. Thus, IC transport variability is a superposition of basin-wide to local processes that influence the velocity field on different time scales.},
	keywords = {AMOC, convection, Irminger Current, Irminger Sea, OSNAP},
	isbn = {2169-9291},
	doi = {10.1029/2021JC018188},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JC018188},
	author = {Fried, Nora and de Jong, M. Femke}
}
