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Radiocarbon as a thermocline proxy for the eastern equatorial Pacific
Author(s) -
Rodgers Keith B.,
Aumont Olivier,
Madec Gurvan,
Menkes Christophe,
Blanke Bruno,
Monfray Patrick,
Orr James C.,
Schrag Daniel P.
Publication year - 2004
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 - 10.1029/2004gl019764
Subject(s) - thermocline , upwelling , oceanography , entrainment (biomusicology) , geology , water mass , climatology , pacific ocean , sea surface temperature , proxy (statistics) , δ18o , environmental science , stable isotope ratio , philosophy , physics , quantum mechanics , machine learning , aesthetics , computer science , rhythm
An ocean model is used to test the idea that sea surface Δ 14 C behaves as a thermocline proxy in the eastern equatorial Pacific. The ORCA2 model, which includes Δ 14 C as a passive tracer, has been forced with reanalysis fluxes over 1948–1999, and the output is compared with a previously reported Galapagos Δ 14 C record. The model reproduces the abrupt increase in the seasonally minimum Δ 14 C in 1976/77 found in the data. This increase is associated with neither a shift of thermocline depth over the NINO3 region, nor a change in the relative proportion of Northern/Southern source waters. Rather, it is due to a decrease in the Sub‐Antarctic Mode Water (SAMW) component of the upwelling water, thereby representing a decrease in entrainment of water from below the base of the directly ventilated thermocline.