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Inverse estimates of anthropogenic CO 2 uptake, transport, and storage by the ocean
Author(s) -
Mikaloff Fletcher S. E.,
Gruber N.,
Jacobson A. R.,
Doney S. C.,
Dutkiewicz S.,
Gerber M.,
Follows M.,
Joos F.,
Lindsay K.,
Menemenlis D.,
Mouchet A.,
Müller S. A.,
Sarmiento J. L.
Publication year - 2006
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2005gb002530
Subject(s) - southern hemisphere , environmental science , latitude , tracer , climatology , northern hemisphere , flux (metallurgy) , ocean current , range (aeronautics) , atmospheric sciences , carbon cycle , oceanography , geology , chemistry , ecology , physics , materials science , geodesy , organic chemistry , ecosystem , nuclear physics , composite material , biology
Regional air‐sea fluxes of anthropogenic CO 2 are estimated using a Green's function inversion method that combines data‐based estimates of anthropogenic CO 2 in the ocean with information about ocean transport and mixing from a suite of Ocean General Circulation Models (OGCMs). In order to quantify the uncertainty associated with the estimated fluxes owing to modeled transport and errors in the data, we employ 10 OGCMs and three scenarios representing biases in the data‐based anthropogenic CO 2 estimates. On the basis of the prescribed anthropogenic CO 2 storage, we find a global uptake of 2.2 ± 0.25 Pg C yr −1 , scaled to 1995. This error estimate represents the standard deviation of the models weighted by a CFC‐based model skill score, which reduces the error range and emphasizes those models that have been shown to reproduce observed tracer concentrations most accurately. The greatest anthropogenic CO 2 uptake occurs in the Southern Ocean and in the tropics. The flux estimates imply vigorous northward transport in the Southern Hemisphere, northward cross‐equatorial transport, and equatorward transport at high northern latitudes. Compared with forward simulations, we find substantially more uptake in the Southern Ocean, less uptake in the Pacific Ocean, and less global uptake. The large‐scale spatial pattern of the estimated flux is generally insensitive to possible biases in the data and the models employed. However, the global uptake scales approximately linearly with changes in the global anthropogenic CO 2 inventory. Considerable uncertainties remain in some regions, particularly the Southern Ocean.