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% Title     : Model Descriptions
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% Author    : Sara Mikaloff Fletcher et al.
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\documentclass[ gbc]{agu2001}


\authorrunninghead{MIKALOFF FLETCHER ET AL.}

\titlerunninghead{AIR-SEA EXCHANGE OF ANTHROPOGENIC CARBON}

\begin{document}

\title{Extended discussion of the between-model variability in the {N}orth
       {A}tlantic}

\authors{S. E. Mikaloff Fletcher, \altaffilmark{1}
 N. Gruber, \altaffilmark{1}
 A. R. Jacobson, \altaffilmark{2}
 S. C. Doney, \altaffilmark{3}
 S. Dutkiewicz, \altaffilmark{4}
 M. Gerber, \altaffilmark{5}
 M. Follows, \altaffilmark{4}
 F. Joos, \altaffilmark{5}
 K. Lindsay, \altaffilmark{6}
 D. Menemenlis, \altaffilmark{7}
 A. Mouchet \altaffilmark{8}
 S. A. M\"uller \altaffilmark{5}
 and J. L. Sarmiento \altaffilmark{2}}



\altaffiltext{1}{Department of Atmospheric and Oceanic Sciences and
Oceanic Sciences and the Institute for Geophysics and Planetary
Physics, University of California, Los Angeles, California, USA.}

\altaffiltext{2}{Atmospheric and Oceanic Sciences Department,
Princeton, New Jersey, USA.}

\altaffiltext{3}{Marine Chemistry and Geochemistry,
Woods Hole Oceanographic Institution, Woods Hole, MA, USA.}

\altaffiltext{4}{Department of Earth, Atmosphere, and Planetary Sciences,
Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.}

\altaffiltext{5}{Climate and Environmental Physics, Physics Institute,
University of Bern, Bern, Switzerland.}

\altaffiltext{6}{Climate and Global Dynamics Division,
National Center for Atmospheric Research, Boulder, Colorado, USA.}

\altaffiltext{7}{Estimating the Circulation and Climate of the Ocean,
Jet Propulsion Laboratory, Pasadena, California, USA.}

\altaffiltext{8}{Astrophysics and Geophysics Institute,
University of Liege, Belgium.}


\begin{article}




Most of the models are in excellent agreement in the Atlantic;
however, the UL model exhibits a different latitudinal distribution
of anthropogenic carbon uptake compared with the other OGCMs used
(Figure 6 of the manuscript and Figure 9 of the online supplement).
This area is composed of the North Atlantic High-, Mid-, and
Low-Latitude Regions (Regions 2-4). Flux into the Arctic Ocean
(Region 1) and into North Atlantic High-Latitudes (Region 2) is the
primary mechanism for anthropogenic carbon  storage in the high
latitude North Atlantic, while the North Atlantic Mid- and
Low-Latitude regions have the strongest signals at mid-latitudes
(Figure 2 of the online supplement). The UL model keeps a larger
portion of the dye injected into the Arctic Ocean and North-Atlantic
High-Latitudes  close to the surface than any of the other
contributing models. As a result, greater anthropogenic uptake in
these regions is required to  match the observed storage of
anthropogenic carbon in the high-latitude North Atlantic.  In order
to balance this high anthropogenic carbon estimate in the North
Atlantic High-Latitude region, the inversion estimates a small
amount of out-gassing from the North Atlantic Mid-Latitude region.
Finally, a  higher uptake is needed in the North Atlantic
Low-Latitude Region to match the observed storage at mid-latitudes.



\end{article}
\end{document}
