@article {2644,
	title = {Upwelling in the Ocean Basins North of the ACC: 1. On the Upwelling Exposed by the Surface Distribution of C-14},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {124},
	year = {2019},
	month = {Apr-04-2020},
	pages = {2591 - 2608},
	abstract = {he upwelling associated with the ocean{\textquoteright}s overturning circulation is hard to observe directly. Here, a large data set of surface C-14 measurements is compiled in order to show where deep water is brought back up to the surface in the ocean basins north of the Antarctic Circumpolar Current (ACC). Maps constructed from the data set show that low-C-14 deep water from the ACC is drawn up to the surface in or near the upwelling zones off Northwest Africa and Namibia in the Atlantic, off Costa Rica and Peru in the Pacific, and in the northern Arabian Sea in the Indian Ocean. Deep water also seems to be reaching the surface in the subarctic Pacific gyre near the Kamchatka Peninsula. The low-C-14 water drawn up to the surface in the upwelling zones is also shown to spread across the ocean basins. It is easily seen, for example, in the western Atlantic off Florida and in the western Pacific off New Guinea and Palau. The spreading allows one to estimate the volumes of upwelling, which, it turns out, are similar to the volumes of large-scale upwelling derived from inverse box models. This means that very large volumes of cool subsurface water are reaching the surface in and near the upwelling zonesmuch larger volumes than would be expected from the local winds.

Plain Language Summary The deep layers of the ocean are filled with cold dense water that sinks from the surface near Antarctica and in the northern North Atlantic. This process is understood reasonably well. The countervailing processthe way that the dense water is brought back up to the surfaceis not as well understood. Oceanographers now agree that the ocean{\textquoteright}s deep water is drawn back up to the surface (upwelled) mainly around Antarctica as part of the wind-driven overturning in the Antarctic Circumpolar Current (ACC). But cool water is also known to reach the surface in upwelling zones around the ocean{\textquoteright}s margins. Here we map the upwelling north of the ACC with the radioactive isotope carbon-14 and show that the deep water upwelled to the surface around Antarctica seems to be drawn up to the surface a second time in the upwelling zones. The water drawn up to the surface in the upwelling zones then flows back to the North Atlantic and sinks again to complete the cycle.},
	keywords = {Ocean circulation, overturning circulation, radiocarbon, Upwelling},
	issn = {2169-9275},
	doi = {10.1029/2018JC014794},
	url = {https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JC014794},
	author = {Toggweiler, J. R. and Druffel, Ellen R. M. and Key, Robert M. and Galbraith, Eric D.}
}
@article {2645,
	title = {Upwelling in the Ocean Basins North of the ACC: 2. How Cool Subantarctic Water Reaches the Surface in the Tropics},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {124},
	year = {2019},
	month = {Apr-04-2020},
	pages = {2609 - 2625},
	abstract = {Large volumes of cool water are drawn up to the surface in the tropical oceans. A companion paper shows that the cool water reaches the surface in or near the upwelling zones off northern and southern Africa and Peru. The cool water has a subantarctic origin and spreads extensively across the Atlantic and Pacific basins after it reaches the surface. Here, we look at the spreading in two low-resolution ocean general circulation models and find that the spreading in the models is much less extensive than observed. The problem seems to be the way the upwelling and the spreading are connected (or not connected) to the ocean{\textquoteright}s large-scale overturning. As proposed here, the cool upwelling develops when warm buoyant water in the western tropics is drawn away to become deep water in the North Atlantic. The drawing away shoals the tropical thermocline in a way that allows cool subantarctic water to be drawn up to the surface along the eastern margins. The amounts of upwelling produced this way exceed the amounts generated by the winds in the upwelling zones by as much as 4 times. Flow restrictions make it difficult for the warm buoyant water in our models to be drawn away.

Plain Language Summary A companion paper uses the radioactive isotope carbon-14 to map the upwelling in the ocean basins north of the Antarctic Circumpolar Current (ACC). It shows that deep water drawn up to the surface to the south of the ACC is drawn up to the surface a second time in a number of upwelling areas in the tropics. In this paper, we attempt to simulate the tropical upwelling in an ocean circulation model and find that it is largely missing. Other circulation features are missing as well. The other features operate on the opposite sides of the ocean basins from the upwelling areas and help carry warm water out of the tropics (outflows). The combination of missing elements leads to a hypothesis about the upwelling mechanism. Our hypothesis is that the tropical upwelling is driven by the outflows and the fact that the warm water being carried away ultimately becomes deep water again in the North Atlantic.},
	keywords = {numerical modeling, Ocean circulation, overturning circulation, Upwelling},
	issn = {2169-9275},
	doi = {10.1029/2018JC014795},
	url = {https://www.researchgate.net/publication/331524382_Upwelling_in_the_Ocean_Basins_north_of_the_ACC_Part_1_On_the_Upwelling_Exposed_by_the_Surface_Distribution_of_D_14_C},
	author = {Toggweiler, J. R. and Druffel, Ellen R. M. and Key, Robert M. and Galbraith, Eric D.}
}
@article {Cook201684,
	title = {Tracing subarctic Pacific water masses with benthic foraminiferal stable isotopes during the \{LGM\} and late Pleistocene},
	journal = {Deep Sea Research Part II: Topical Studies in Oceanography},
	volume = {125{\textendash}126},
	year = {2016},
	note = {Plio-Pleistocene Paleoceanography of the Bering Sea},
	pages = {84 - 95},
	abstract = {Abstract As the largest ocean basin, the Pacific helps to set the global climate state, since its circulation affects mean ocean properties, air{\textendash}sea partitioning of carbon dioxide, and the distribution of global oceanic poleward heat transport. There is evidence that during the Last Glacial Maximum (LGM) the subarctic Pacific contained a better-ventilated, relatively fresh intermediate water mass above ~2000 m that may have formed locally. The source and spatial extent of this water mass is not known, nor do we know how formation of this water mass varied during Pleistocene glaciations with different orbital and ice sheet boundary conditions. Here we present a 0.5 My multi-species benthic stable isotope record from Site \{U1345\} (1008 m) on the northern Bering slope and a 1.0 My record from \{U1339\} (1868 m) from the Umnak Plateau in the southeastern basin. We find that the relatively well-ventilated low-δ18O intermediate water reaches 1000 m in the Bering Sea during MIS2, but that the hydrographic divide between this water mass and poorly-ventilated deep water was shallower than 1000 m for earlier glaciations. We also compare Bering Sea piston core and {\.I}ODP\} Expedition 323 Uvigerina data from the Holocene and \{LGM\} with the modern hydrography, and to previously published profiles from the Okhotsk Sea and Emperor Seamounts. We find that the carbon and oxygen stable isotope signatures of well-ventilated water in the Bering and Okhotsk Seas are distinct, suggesting that there may have been intermediate water formation in both basins during the LGM.},
	keywords = {Ocean circulation},
	issn = {0967-0645},
	doi = {http://doi.org/10.1016/j.dsr2.2016.02.006},
	url = {http://www.sciencedirect.com/science/article/pii/S0967064516300157},
	author = {Mea S. Cook and A. Christina Ravelo and Alan Mix and Ian M. Nesbitt and Nari V. Miller}
}
@article {2044,
	title = {Radiocarbon and stable isotope constraints on Last Glacial Maximum and Younger Dryas ventilation in the western North Atlantic},
	journal = {Paleoceanography},
	volume = {19},
	year = {2004},
	note = {870dfTimes Cited:72
Cited References Count:60
},
	month = {Nov 3},
	abstract = {[1] Foraminiferal abundance, C-14 ventilation ages, and stable isotope ratios in cores from high deposition rate locations in the western subtropical North Atlantic are used to infer changes in ocean and climate during the Younger Dryas (YD) and Last Glacial Maximum (LGM). The delta(18)O of the surface dwelling planktonic foram Globigerinoides ruber records the present-day decrease in surface temperature (SST) of similar to 4 degreesC from Gulf Stream waters to the northeastern Bermuda Rise. If during the LGM the modern delta(18)O/salinity relationship was maintained, this SST contrast was reduced to 2 degreesC. With LGM to interglacial delta(18)O changes of at least 2.2parts per thousand, SSTs in the western subtropical gyre may have been as much as 5 degreesC colder. Above similar to 2.3 km, glacial delta(13)C was higher than today, consistent with nutrient-depleted ( younger) bottom waters, as identified previously. Below that, delta(13)C decreased continually to - 0.5parts per thousand, about equal to the lowest LGM delta(13)C in the North Pacific Ocean. Seven pairs of benthic and planktonic foraminiferal C-14 dates from cores > 2.5 km deep differ by 1100 +/- 340 years, with a maximum apparent ventilation age of similar to 1500 years at 4250 m and at similar to 4700 m. Apparent ventilation ages are presently unavailable for the LGM < 2.5 km because of problems with reworking on the continental slope when sea level was low. Because LGM \&delta;C-13 is about the same in the deep North Atlantic and the deep North Pacific, and because the oldest apparent ventilation ages in the LGM North Atlantic are the same as the North Pacific today, it is possible that the same water mass, probably of southern origin, flowed deep within each basin during the LGM. Very early in the YD, dated here at 11.25 +/- 0.25 ( n = 10) conventional C-14 kyr BP ( equal to 12.9 calendar kyr BP), apparent ventilation ages < 2.3 km water depth were about the same as North Atlantic Deep Water today. Below similar to 2.3 km, four YD pairs average 1030 +/- 400 years. The oldest apparent ventilation age for the YD is 1600 years at 4250 m. This strong contrast in ventilation, which indicates a front between water masses of very different origin, is similar to glacial profiles of nutrient-like proxies. This suggests that the LGM and YD modes of ocean circulation were the same.},
	keywords = {benthic foraminifera, deep-sea sediments, ice-age, Ocean circulation, ocean ventilation, pacific-ocean, radiocarbon, SARGASSO SEA, southern-ocean, Thermohaline circulation, united-states, water circulation, western north atlantic},
	isbn = {0883-8305},
	doi = {10.1029/2004PA001029},
	url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2\&amp;SrcAuth=Alerting\&amp;SrcApp=Alerting\&amp;DestApp=WOS\&amp;DestLinkType=FullRecord;UT=WOS:000225033500003},
	author = {Keigwin, L. D.}
}
@article {2076,
	title = {Persistence of Gulf Stream separation during the Last Glacial Period: Implications for current separation theories},
	journal = {Journal of Geophysical Research-Oceans},
	volume = {108},
	year = {2003},
	note = {690nvTimes Cited:14
Cited References Count:56
},
	month = {Jun 4},
	abstract = {[1] We present stable oxygen isotope ratio (delta(18)O) measurements on deep-dwelling planktonic foraminifera from the western margin of the North Atlantic in order to reconstruct the latitude at which the Gulf Stream separated from the western boundary of the Atlantic Ocean in the past. The modern separation latitude can be reconstructed within one degree from delta(18)O measured on the fossil shells of deep-dwelling planktonic foraminifera Globorotalia truncatulinoides from the Holocene sediments representing the past 10,000 years of mild climate conditions similar to today. The separation latitude is captured in a sharp delta(18)O gradient, which reflects the prominent hydrographic change across the boundary between the warm waters south and east of the Gulf Stream and the cold Slope Water to the north. The latitudinal delta(18)O profile from approximately the Last Glacial Maximum shows that the Gulf Stream separated from the coast near Cape Hatteras at almost the same latitude as it does today. We assess our finding in light of existing Gulf Stream separation theories and conclude that one of the theories, the wind-induced separation mechanism, is not consistent with our paleoceanographic reconstruction.},
	keywords = {cape-hatteras, deep-ocean, gulf stream separation, Last glacial maximum, marine sediment cores, north-atlantic, Ocean circulation, oxygen isotope composition, oxygen isotopic composition, past 21,000 years, planktonic foraminifera, planktonic-foraminifera, SARGASSO SEA, western boundary current, western boundary undercurrent, wind-driven},
	isbn = {0148-0227},
	doi = {10.1029/2001JC000861},
	author = {Matsumoto, K. and Lynch-Stieglitz, J.}
}
@conference {1279,
	title = {An Ocean-Wide DIC-13 Data Set},
	booktitle = {2000 Ocean Sciences Meeting, San Antonio, TX (USA), 24-28 Jan 2000},
	year = {2000},
	note = {Date revised - 2007-04-01SuppNotes - Abstracts available.Last updated - 2016-12-21},
	month = {January 2000},
	publisher = {American Geophysical Union, 2000 Florida Ave., N.W. Washington, DC 20009 USA},
	organization = {American Geophysical Union, 2000 Florida Ave., N.W. Washington, DC 20009 USA},
	abstract = {High quality DIC-13 measurements were made throughout the world{\textquoteright}s oceans at the University of Washington (UW) and the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility during both the OACES and WOCE programs. We are currently merging these two data sets which represent 25000 individual DIC- 13 measurements from 1260 stations. We will present the inter-laboratory calibration and standardization data. Based on 135 measurements on CO2 gas extracted at UW, the mean offset between the two labs is 0.01 o/oo, similar to the offset observed from an exchange of DIC standards (0.012 o/oo). Stations measured by both laboratories will also be examined for offsets, although one comparison in the Indian Ocean shows no significant differences. We will present our progress towards a global atlas of DIC-13, primarily maps of the merged data sets in the Pacific, Southern, and Indian Oceans. In this poster we will concentrate on regions that have been under-sampled in the past, e.g. the Southern Ocean. Additionally, we will examine the relationship of DIC-13 to PO4 and to DIC-14. A preliminary analysis of DIC-13 and PO4 from three WOCE lines in the Pacific indicates that the expected relationship is observed in the deep waters and that the data from different water masses occupy well-defined regions of the graph. We are examining the potential for using the relationship between DIC-14 and DIC-13 to improve our understanding of the penetration of bomb radiocarbon into the ocean as well as fundamental processes in the deep ocean. The relationship is complex yet the data from shallow to intermediate depths (100 to 1000m) follow two distinct parallel lines that are related to the hemisphere in which},
	keywords = {carbon cycling, Carbon dioxide, Deep water, dissolved inorganic carbon, ISW, Indian Ocean, Marine, Mass Spectrometry, Ocean circulation, Phosphates, PS, Antarctic Ocean, Q2 09146:TSD distribution, water masses and circulation, Stable isotopes, Standardization, Water masses, World Ocean, World Ocean Circulation Experiment (WOCE)},
	url = {https://search.proquest.com/docview/19610793?accountid=29119},
	author = {McNichol, A P and Quay, P D and Stuart, D R and Sonnerup, R E and Key, R M}
}
