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Titel |
Detecting an external influence on recent changes in oceanic oxygen using an optimal fingerprinting method |
VerfasserIn |
O. D. Andrews, N. L. Bindoff, P. R. Halloran, T. Ilyina, C. Quéré |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 10, no. 3 ; Nr. 10, no. 3 (2013-03-19), S.1799-1813 |
Datensatznummer |
250018156
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Publikation (Nr.) |
copernicus.org/bg-10-1799-2013.pdf |
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Zusammenfassung |
Ocean deoxygenation has been observed in all major ocean basins over the past
50 yr. Although this signal is largely consistent with oxygen changes
expected from anthropogenic climate change, the contribution of external
forcing to recent deoxygenation trends relative to natural internal
variability is yet to be established. Here we conduct a formal optimal
fingerprinting analysis to investigate if external forcing has had a
detectable influence on observed dissolved oxygen concentration ([O2])
changes between ∼1970 and ∼1992 using simulations from two
Earth System Models (MPI-ESM-LR and HadGEM2-ES). We detect a response to
external forcing at a 90% confidence level and find that observed
[O2] changes are inconsistent with internal variability as simulated by
models. This result is robust in the global ocean for depth-averaged (1-D)
zonal mean patterns of [O2] change in both models. Further analysis with
the MPI-ESM-LR model shows similar positive detection results for
depth-resolved (2-D) zonal mean [O2] changes globally and for the
Pacific Ocean individually. Observed oxygen changes in the Atlantic Ocean are
indistinguishable from natural internal variability. Simulations from both
models consistently underestimate the amplitude of historical [O2]
changes in response to external forcing, suggesting that model projections
for future ocean deoxygenation may also be underestimated. |
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