@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.}
}
@book {2557,
	title = {Coral Reefs of the WorldCoral Reefs of the Eastern Tropical PacificHolocene Reef Development in the Eastern Tropical Pacific},
	volume = {8},
	year = {2016},
	pages = {177 - 201},
	publisher = {Springer Netherlands},
	organization = {Springer Netherlands},
	address = {Dordrecht},
	abstract = {Contrary to early assessments, the eastern tropical Pacific (ETP) is not devoid of well-developed reefs. Significant accumulations of Holocene reef framework are present throughout the region, although they tend to be poorly consolidated, lack the submarine cementation common on most reefs elsewhere in the world, and are subject to considerable bioerosion. These reef frameworks began accreting as early as 7000 years ago. The thickest accumulations of Pocillopora frameworks occur in coastal areas of Mexico, Costa Rica, Panama, and Colombia, but reefs composed of massive corals{\textemdash}species of Porites, Pavona, or Gardineroseris{\textemdash}are present throughout the region. Reef development in the ETP is limited by a variety of characteristics of the physical environment. Because of high turbidity in most areas, reef development is generally restricted to less than ~10 m depth. The spatial extent of reefs in the ETP is also limited from the combined influences of wave action and upwelling. Most reefs in the ETP are only a few hectares in size and the best-developed reefs generally occur in areas sheltered from strong oceanic influence. Upwelling also influences long-term trends in reef development in the region. There does not appear to be a significant impact of upwelling on the millennial-scale growth rates of Panamanian reefs; however, reefs in upwelling environments typically have thinner frameworks than nearby reefs in non-upwelling environments. Furthermore, upwelling may have contributed to a historic shutdown of reef development in Costa Rica and Panama. Although both ecological and oceanographic disturbances have had some impact on the long-term development of reefs in the ETP, the most important control on reef development in this region throughout the Holocene has most likely been the El Ni{\~n}o{\textendash}Southern Oscillation (ENSO). ENSO activity{\textemdash}especially that of the 1982{\textendash}83 and 1997{\textendash}98 El Ni{\~n}o events{\textemdash}has shaped the landscape of coral reefs across the ETP both in recent decades and in the past. Reefs in Pacific Panama and Costa Rica experienced a 2500-year hiatus in vertical growth beginning ~4100 years ago as a result of enhanced ENSO activity. Although the degree of framework accumulation and rate of reef accretion in some parts of the ETP are more similar to that of the western Atlantic than previously thought, the region still remains a marginal environment for reef development. Given the dominant role that climatic variability has played in controlling reef development in the past, the future of reefs in the ETP under accelerating climate change remains uncertain.},
	keywords = {El Ni{\~n}o, Latin American reefs, paleoecology, Reef accretion, Southern Oscillation, Upwelling},
	isbn = {978-94-017-7498-7},
	issn = {2213-719X},
	doi = {10.1007/978-94-017-7499-410.1007/978-94-017-7499-4_6},
	url = {https://link.springer.com/chapter/10.1007\%2F978-94-017-7499-4_6},
	author = {Toth, Lauren T. and Macintyre, Ian G. and Aronson, Richard B.},
	editor = {Glynn, Peter W. and Manzello, Derek P. and Enochs, Ian C.}
}
