Publication Date:
2018-06-12
Description:
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. ©2018. American Geophysical Union. All Rights Reserved.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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