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.
Suggested CitationJournal of Geophysical Research 115 (2010): C11015
Showing items related by title, author, creator and subject.
The fraction of water last ventilated in a given region regardless of the time elapsed since ventilation (in practice, younger than 4000 years) based on samples collected from R/V Knorr cruises KN199-04 and KN204-01 during 2010-2011 Smethie Jr., William M.; Holzer, Mark; Ting, Yu-Heng (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: email@example.com, 2020-05-27)Water mass fractions and ages calculated from hydrographic and tracer data using a maximum-entropy inversion technique. This dataset contains the fraction of water last ventilated in a given region regardless of the time ...
Temporal evolution of tritium-³He age in the North Atlantic : implications for thermocline ventilation Robbins, Paul E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-09)This thesis is a study of the physical mechanisms that ventilate the subtropical thermocline of the eastern North Atlantic. The starting point is an analysis of the existent historical database of natural and anthropogenic ...
Goodkin, Nathalie F.; Druffel, Ellen R. M.; Hughen, Konrad A.; Doney, Scott C. (Nature Publishing Group, 2012-05-01)Ventilation and mixing of oceanic gyres is important to ocean-atmosphere heat and gas transfer, and to mid-latitude nutrient supply. The rates of mode water formation are believed to impact climate and carbon exchange ...