Constraining ventilation during deepwater formation using deep ocean measurements of the dissolved gas ratios 40Ar/36Ar, N2/Ar, and Kr/Ar
Nicholson, David P.
Hamme, Roberta C.
MetadataShow full item record
The concentration of inert gases and their isotopes in the deep ocean are useful as tracers of air-sea gas exchange during deepwater formation. ΔKr/Ar, ΔN2/Ar, and δ40Ar were measured in deep profiles of samples collected in the northwest Pacific, subtropical North Pacific and tropical Atlantic oceans. For the ocean below 2000 m, we determined a mean ΔKr/Ar composition of −0.96% ± 0.16%, a mean ΔN2/Ar of 1.29% ± 0.21% relative to equilibrium saturation, and for δ40Ar a value of 1.188‰ ± 0.055‰ relative to air. These data are used to constrain high-latitude ventilation processes in the framework of three-box and seven-box ocean models. For the three-box model tracer data, we constrain the appropriate surface area of the high-latitude region in both models to be 3.6% (+2.5%, −1.7%) of ocean surface area and the bubble air injection rate to be 22.7 (+8.8, −7.3) mol air m−2 yr−1. Results for the seven-box model were similar, with a high-latitude area of 3.3% (+2.2%, −1.3%). Our results provide geochemical support for suggestions that the effective area of high-latitude ventilation is much smaller than the region of elevated preformed nutrients and demonstrate that noble gases strongly constrain the ocean solubility pump. Reducing high-latitude surface area weakens the CO2 solubility pump in the box models and limits communication between the atmosphere and deep ocean. These tracers should be useful constraints on high-latitude ventilation and the strength of the solubility pump in more complex ocean general circulation models.
Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 115 (2010): C11015, doi:10.1029/2010JC006152.
Showing items related by title, author, creator and subject.
Response of the North Atlantic thermohaline circulation and ventilation to increasing carbon dioxide in CCSM3 Bryan, Frank O.; Danabasoglu, Gokhan; Nakashiki, Norikazu; Yoshida, Yoshikatsu; Kim, Dong-Hoon; Tsutsui, Junichi; Doney, Scott C. (American Meteorological Society, 2006-06-01)The response of the North Atlantic thermohaline circulation to idealized climate forcing of 1% per year compound increase in CO2 is examined in three configurations of the Community Climate System Model version 3 that ...
Radiocarbon and stable isotope constraints on Last Glacial Maximum and Younger Dryas ventilation in the western North Atlantic Keigwin, Lloyd D. (American Geophysical Union, 2004-11-03)Foraminiferal abundance, 14C 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 ...
Trossman, David S.; Thompson, LuAnne; Kelly, Kathryn A.; Kwon, Young-Oh (American Meteorological Society, 2009-10)Lagrangian estimates for ventilation rates in the Gulf Stream Extension using Argo and World Ocean Circulation Experiment/Atlantic Climate and Circulation Experiment (WOCE/ACCE) float data, scatterometer (QuikSCAT) wind ...