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Changes to the Air‐Sea Flux and Distribution of Radiocarbon in the Ocean Over the 21st Century
Author(s) -
Khatiwala Samar,
Graven Heather,
Payne Sarah,
Heimbach Patrick
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl078172
Subject(s) - ocean gyre , radiocarbon dating , ocean current , hydrography , oceanography , climatology , environmental science , flux (metallurgy) , carbon cycle , carbon flux , sea surface temperature , thermohaline circulation , subtropics , ocean general circulation model , geology , general circulation model , climate change , ecosystem , paleontology , materials science , fishery , metallurgy , biology , ecology
We investigate the spatiotemporal evolution of radiocarbon (Δ 14 C) in the ocean over the 21st century under different scenarios for anthropogenic CO 2 emissions and atmospheric CO 2 and radiocarbon changes using a 3‐D ocean carbon cycle model. Strong decreases in atmospheric Δ 14 C in the high‐emission scenario result in strong outgassing of 14 C over 2050–2100, causing Δ 14 C spatial gradients in the surface ocean and vertical gradients between the surface and intermediate waters to reverse sign. Surface Δ 14 C in the subtropical gyres is lower than Δ 14 C in Pacific Deep Water and Southern Ocean surface water in 2100. In the low‐emission scenario, ocean Δ 14 C remains slightly higher than in 1950 and relatively constant over 2050–2100. Over the next 20 years we find decadal changes in Δ 14 C of −30‰ to +5‰ in the upper 2 km of the ocean, which should be detectable with continued hydrographic surveys. Our simulations can help in planning future observations, and they provide a baseline for investigating natural or anthropogenic changes in ocean circulation using ocean Δ 14 C observations and models.