@article{d87bee58faa94795b955bb10d82f9301,
title = "Evaluating CMIP5 ocean biogeochemistry and Southern Ocean carbon uptake using atmospheric potential oxygen: Present-day performance and future projection",
abstract = "Observed seasonal cycles in atmospheric potential oxygen (APO ~ O2 + 1.1 CO2) were used to evaluate eight ocean biogeochemistry models from the Coupled Model Intercomparison Project (CMIP5). Model APO seasonal cycles were computed from the CMIP5 air-sea O2 and CO2 fluxes and compared to observations at three Southern Hemisphere monitoring sites. Four of the models captured either the observed APO seasonal amplitude or phasing relatively well, while the other four did not. Many models had an unrealistic seasonal phasing or amplitude of the CO2 flux, which in turn influenced APO. By 2100 under RCP8.5, the models projected little change in the O2 component of APO but large changes in the seasonality of the CO2 component associated with ocean acidification. The models with poorer performance on present-day APO tended to project larger net carbon uptake in the Southern Ocean, both today and in 2100.",
keywords = "APO, CMIP5 models, Southern Ocean carbon cycle, air-sea fluxes, carbon cycle, ocean carbon sink",
author = "Nevison, {C. D.} and M. Manizza and Keeling, {R. F.} and Stephens, {B. B.} and Bent, {J. D.} and J. Dunne and T. Ilyina and M. Long and Laure Resplandy and J. Tjiputra and S. Yukimoto",
note = "Funding Information: The authors gratefully acknowledge the CMIP5 ocean modelers for providing the output that made this project possible. In particular, we thank Keith Lindsay, Paul Halloran, and Christoph Heinze for their assistance. We are also grateful to Anna Cabre, Mo Green, and Irina Marinov for help in obtaining CMIP5 output, to Andrew Schuh for help with the GEOS-Chem simulations, and to two anonymous reviewers for their helpful comments. This work utilized the Janus supercomputer, which is supported by the National Science Foundation (award CNS-0821794) and the University of Colorado Boulder. The Janus supercomputer is a joint effort of the University of Colorado Boulder, the University of Colorado Denver, and the National Center for Atmospheric Research. The National Center for Atmospheric Research is sponsored by the National Science Foundation. C.D.N. and M.M. acknowledge support from NASA Ocean Biology and Biogeochemistry grant NNX11AL73G and J.T. acknowledges Norwegian Research Council-funded ORGANIC project (239965). This study is a contribution to the EU H2020 project CRESCENDO (grant 641816). The data used are listed in the references and supporting information. The APO observations are available from the Scripps Institution of Oceanography under http://scrippso2.ucsd.edu and http://scrippsco2.ucsd.edu. The CMIP5 output fields are available from http://cmip-pcmdi.llnl.gov/cmip5/data_portal. html. Publisher Copyright: {\textcopyright} 2016. American Geophysical Union. All Rights Reserved.",
year = "2016",
month = mar,
day = "16",
doi = "10.1002/2015GL067584",
language = "English (US)",
volume = "43",
pages = "2077--2085",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "5",
}