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% Title     : Model Descriptions
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% Author    : Sara Mikaloff Fletcher et al.
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\authorrunninghead{MIKALOFF FLETCHER ET AL.}
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\titlerunninghead{AIR-SEA EXCHANGE OF ANTHROPOGENIC CARBON}
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\begin{document}

\title{Model Descriptions}

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%  AUTHORS AND AFFILIATIONS
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 \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}

\section{Bern3D: }

The Bern3D ocean model is a computationally-efficient, 3-dimensional
coarse resolution (36 by 36 grid boxes with 32 vertical layers),
frictional-geostrophic balance ocean model (\cite{Mueller_jclim_2005}).
It is based on the ocean model developed by \cite{Edwards_jpo_1998} and
\cite{Edwards_cd_2005}. The Bern3D model has
been updated to resolve the seasonal cycle and includes an implicit
numerical scheme for vertical transport allowing time steps of the
order of weeks and an updated convection scheme. The implementation of
the formulation of eddy-induced transport (\cite{Griffies_jpo_1998b}) used
by \cite{Edwards_cd_2005} was modified to allow an independent
tuning of the respective parameters for isopycnal mixing and
eddy-induced transport.

The model was tuned using data-based metrics defined by \cite{Matsumoto_grl_2004}.
These metrics include radiocarbon signatures for
North Atlantic Deep Water, North Pacific Deep Water and Circumpolar
Deep Water as well as inventories of CFC-11 in the Indo-Pacific north
and south of 40S. The model simulates these five values within their
data-based uncertainties. (\cite{Mueller_jclim_2005}).



\section{ECCO : Estimating the Circulation and Climate of the Ocean}

The ECCO (Estimating the Circulation and Climate of the Ocean) consortium
contributed a model simulation driven by air-sea fluxes of heat, freshwater,
and momentum estimated using ocean data assimilation (\cite{Stammer_jgr_2004}).
Specifically, surface fluxes were estimated from an adjoint-method 1992-2002
optimization using a quasi-global ocean configuration (80°S-80°N) of the
MIT GCM with 23 vertical levels and 1° horizontal grid spacing.  Data
constraints include ERS-1, ERS-2, and TOPEX/Poseidon sea-surface height (SSH)
anomalies, TOPEX/Poseidon time-mean SSH, Reynolds and Smith [1994] and TMI sea
surface temperature, surface boundary fluxes (wind stress, heat, and fresh
water) from the NCEP reanalysis, WOCE, XBT, and ARGO in-situ hydrography, the
Levitus and Boyer [1994] climatologies of temperature and salinity, time-mean
surface drifter data, and ERS/NSCAT/QSCAT estimates of wind stress.  Tracer
Green functions are computed on the 80°S-80°N, 23-level, 1° grid by perpetual
cycling of the 1992-2002 surface fluxes estimated by ECCO.

\section{MIT}

The \mit\ (Massachusetts Institute of Technology) GCM solves the incompressible
Navier-Stokes equation on a C-grid with an optional hydrostatic equation.
Mesoscale eddy transfer effects are represented using a scheme related to the
\cite{Gent_jpo_1990} parameterization.  This parameterization scheme reflects
the strong regional variability of ocean eddy activity (\cite{Visbeck_jpo_1997})
and employs variable mixing coefficients from \cite{Green_qjrms_1970} and
\cite{Stone_jatmsci_1972}. The convective adjustment scheme of
\cite{Large_revgeo_1994} is used to represent vertical turbulent mixing in the
surface mixed layer.

For this study, we use a model configuration that is very similar to the
configuration used for OCMIP.  The model has a horizontal resolution of 2.8\dg\
and 15 vertical levels.  Since OCMIP, there have been three changes to the
Model: the model code has been improved to allow for more integrated handling
of tracers, the wind-stress forcing has been changed from
\cite{Hellerman_jpo_1983} to ECMWF climatology wind fields, and the
bathymetry at the ocean floor has been changed from a partial-cell scheme,
which represent ocean topography more accurately, to a full-cell only
approach. The changes in the wind stress fields are expected to improve flow
through the Drake passage and residual flow in the Southern Ocean, which will
lead to changes in tracer uptake in the Southern Ocean.  The bathymetric
changes are expected to causes  only minor differences in the deep flow at the
coarse resolution used here.

\section{NCAR}

The NCAR (National Center for Atmospheric Research) modeling group used a
coarse resolution version of the ocean model component of the
Community Climate System Model (CCSM), which is based on the Parallel Ocean
Program (POP) GCM (\cite{Smith_1992, Dukowicz_aotech_1993,Dukowicz_jgr_1994}).
Mesoscale eddy mixing is represented by the Gent-McWilliams parameterization
scheme(\cite{Gent_jpo_1990,Danabasoglu_sci_1994}).  The model also employs the
\cite{Large_revgeo_1994} parameterization of the surface boundary layer
dynamics, the anisotropic horizontal velocity of \cite{Large_jpo_2000}, and
the bottom boundary layer dynamics of \cite{Doney_jpo_2002}. The air-sea
bulk forcing is based on satellite observations and NCEP reanalysis data
(\cite{Large_jpo_1997}).

The coarse resolution version of the model was used here, which has a
horizontal resolution of 3.6\dg x 1.85 \dg and 25 vertical levels.
This model has been compared with a range of other OGCMs in OCMIP
(\cite{Dutay_ocemod_2002, Doney_gbc_2004}), and has been shown to effectively
reproduce many major features of climatic relevance such as surface fluxes,
water mass transformations and mixed layer depths, mean and seasonal water
mass properties, high-latitude deep convection patterns, and meridional ocean
heat and freshwater transports (\cite{Gent_jclim_1998}).

\section{PRINCE}

The PRINCE (Princeton University) group contributed five different versions of
the Geophysical Fluid Dynamics Laboratory Modular Ocean Model Version 3 (MOM3)
(\cite{Pacanowski_1998}).  MOM3 is a seasonal model forced by seasonally
varying wind-stress. Surface temperature and salinity fiends are forced with a
hybrid between restoring boundary conditions to climatological values and flux
boundary conditions based on the seasonally varying heat and freshwater fluxes
of \cite{DaSilva_1994}.  Lateral advection due to sub-gridscale eddies is
parameterized following \cite{Gent_jpo_1995} and implemented following
\cite{Griffies_jpo_1998}. The functional form of the explicit vertical
diffusivities is prescribed following \cite{Bryan_jgr_1979}.

The five configurations of MOM3, which are described in detail by
\cite{Gnanadesikan_dsrII_2002} and \cite{Gnanadesikan_gbc_2004},
share the same essential representation
of model transport, but employ different parameters representing the vertical
and along-isopycnal diffusivities, salinity restoring values, wind fields, and
topography.  These differences are summarized in the Configuration Summary
Table, also included in this folder. \cite{Matsumoto_grl_2004} have shown that these five configurations of MOM generally span the range of models used in
OCMIP with respect to transport of CFC's, radiocarbon, and anthropogenic carbon.The LL version was included in OCMIP (\cite{Dutay_ocemod_2002, Doney_gbc_2004}).


%\bibliography{ref_sf}
%\bibliographystyle{agu}
\begin{thebibliography}{29}
\expandafter\ifx\csname natexlab\endcsname\relax\def\natexlab#1{#1}\fi



\bibitem[{{\it Bryan and Lewis\/}(1979)}]{Bryan_jgr_1979}
Bryan, K., and L.~J. Lewis, A water mass model of the world ocean, {\it J.
  Geophys. Res.\/}, {\it 84\/}, 2503--2517, 1979.

\bibitem[{{\it da~Silva et~al.\/}(1994){\it da~Silva, Young, and
  Levitus\/}}]{DaSilva_1994}
da~Silva, A.~M., C.~C. Young, and S.~Levitus, Atlas of surface marine data
  1994. volume 1: Algorithms and procedures, {\it Tech. Rep. NOAA Atlas NESDIS
  6\/}, Natl. Oceanic and Atmos. Admin., Washington, D.C., 1994.

\bibitem[{{\it Danabasoglu et~al.\/}(1994){\it Danabasoglu, McWilliams, and
  Gent\/}}]{Danabasoglu_sci_1994}
Danabasoglu, G., J.~C. McWilliams, and P.~R. Gent, The role of mesoscale tracer
  transports in the global ocean circulation, {\it Science\/}, {\it 264\/},
  1123--1126, 1994.

\bibitem[{{\it Doney et~al.\/}(2004)}]{Doney_gbc_2004}
Doney, S., et~al., Evaluating global ocean carbon models: The importance of
  realistic physics, {\it Global Biogeochem. Cycles\/}, {\it 18\/}, GB3017,
  doi:10.1029/2003GB002,150, 2004.

\bibitem[{{\it Doney and Hecht\/}(2002)}]{Doney_jpo_2002}
Doney, S.~C., and M.~W. Hecht, Antarctic bottom water formation and deep water
  chlorofluorocarbon distributions in a global climate model, {\it J. Phys.
  Oceanogr.\/}, 2002, in press.

\bibitem[{{\it Dukowicz and Smith\/}(1994)}]{Dukowicz_jgr_1994}
Dukowicz, J.~K., and R.~D. Smith, Implicit free-surface method for the
  {B}ryan-{C}ox-{S}emtner ocean model, {\it J. Geophys. Res.\/}, {\it 99\/},
  7991--8014, 1994.

\bibitem[{{\it Dukowicz et~al.\/}(1993){\it Dukowicz, Smith, and
  Malone\/}}]{Dukowicz_aotech_1993}
Dukowicz, J.~K., R.~D. Smith, and R.~C. Malone, A reformulation and
  implementation of the {B}ryan-{C}ox-{S}emtner ocean model on the connection
  machine, {\it Atmos. Ocean. Tech.\/}, {\it 10\/}, 195--208, 1993.

\bibitem[{{\it Dutay et~al.\/}(2002)}]{Dutay_ocemod_2002}
Dutay, J.-C., et~al., Evaluation of ocean model ventilation with {CFC}-11:
  comparison of 13 global ocean models, {\it Ocean Modelling\/}, {\it 4\/},
  89--120, 2002.

\bibitem[{{\it Edwards and Marsh\/}(2005)}]{Edwards_cd_2005}
Edwards, N.~R., and R.~Marsh, Uncertainties due to transport-parameter
  sensitivity in an efficient 3-d ocean-climate model, {\it Clim. Dyn.\/}, {\it
  24\/}, 415--433, 2005.

\bibitem[{{\it Edwards et~al.\/}(1998){\it Edwards, Willmott, and
  Killworth\/}}]{Edwards_jpo_1998}
Edwards, N.~R., A.~J. Willmott, and P.~D. Killworth, On the role of topography
  and wind stress on the stability of the thermohaline circulation, {\it J.
  Phys. Oceanogr.\/}, {\it 28\/}, 756--778, 1998.

\bibitem[{{\it Gent and McWilliams\/}(1990)}]{Gent_jpo_1990}
Gent, P.~R., and J.~C. McWilliams, Isopycnal mixing in ocean circulation
  models, {\it J. Phys. Oceanogr.\/}, {\it 20\/}, 150--155, 1990.

\bibitem[{{\it Gent et~al.\/}(1995){\it Gent, Willebrand, McDougall, and
  McWilliams\/}}]{Gent_jpo_1995}
Gent, P.~R., J.~Willebrand, T.~J. McDougall, and J.~C. McWilliams,
  Parameterizing eddy-induced tracer transports in ocean circulation models,
  {\it J. Phys. Oceanogr.\/}, {\it 25\/}, 463--474, 1995.

\bibitem[{{\it Gent et~al.\/}(1998){\it Gent, Bryan, Danabasoglu, Doney,
  Holland, Large, and McWilliams\/}}]{Gent_jclim_1998}
Gent, P.~R., F.~O. Bryan, G.~Danabasoglu, S.~C. Doney, W.~R. Holland, W.~G.
  Large, and J.~C. McWilliams, The {NCAR} climate system model global ocean
  component, {\it J. Clim.\/}, {\it 11\/}, 1287--1306, 1998.

\bibitem[{{\it Gnanadesikan et~al.\/}(2002){\it Gnanadesikan, Gruber, Slater,
  and Sarmiento\/}}]{Gnanadesikan_dsrII_2002}
Gnanadesikan, A., N.~Gruber, R.~D. Slater, and J.~L. Sarmiento, Oceanic
  vertical exchange and new production: A comparison between model results and
  observations, {\it Deep-Sea Res. II\/}, {\it 49\/}, 363--401, 2002.

\bibitem[{{\it Gnanadesikan et~al.\/}(2004){\it Gnanadesikan, Dunne, Key,
  Matsumoto, Sarmiento, Slater, and Swathi\/}}]{Gnanadesikan_gbc_2004}
Gnanadesikan, A., J.~P. Dunne, R.~M. Key, K.~Matsumoto, J.~L. Sarmiento, R.~D.
  Slater, and P.~S. Swathi, Oceanic ventilation and biogeochemical cycling:
  Understanding the physical mechanisms that produce realistic distributions of
  tracers and productivity, {\it Global Biogeochem. Cycles\/}, {\it 18\/},
  2004, gB4010, doi:10.1029/2003GB002097.

\bibitem[{{\it Green\/}(1970)}]{Green_qjrms_1970}
Green, J. S.~A., Transfer properties of the large-scale eddies of the general
  circulation of the atmosphere, {\it Q. J. R. Meteor. Soc.\/}, {\it 96\/},
  463--474, 1970.

\bibitem[{{\it Griffies\/}(1998)}]{Griffies_jpo_1998b}
Griffies, S.~M., The {Gent-McWilliams} skew flux, {\it J. Phys. Oceanogr.\/},
  {\it 28\/}, 831--841, 1998.

\bibitem[{{\it Griffies et~al.\/}(1998){\it Griffies, Gnanadesikan, Pacanowski,
  Larichev, Dukowicz, and Smith\/}}]{Griffies_jpo_1998}
Griffies, S.~M., A.~Gnanadesikan, R.~C. Pacanowski, V.~Larichev, J.~K.
  Dukowicz, and R.~D. Smith, Isoneutral diffusion in a z-coordinate ocean
  model, {\it J. Phys. Oceanogr.\/}, {\it 28\/}, 805--830, 1998.

\bibitem[{{\it Hellerman and Rosenstein\/}(1983)}]{Hellerman_jpo_1983}
Hellerman, S., and M.~Rosenstein, Normal monthly wind stress over the world
  ocean with error estimates, {\it J. Phys. Oceanogr.\/}, {\it 13\/},
  1093--1104, 1983.

\bibitem[{{\it Large et~al.\/}(1994){\it Large, McWilliams, and
  Doney\/}}]{Large_revgeo_1994}
Large, W.~G., J.~C. McWilliams, and S.~C. Doney, Oceanic vertical mixing: A
  review and a model with a nonlocal boundary layer parameterization, {\it Rev.
  Geophys.\/}, {\it 32\/}, 363--403, 1994.

\bibitem[{{\it Large et~al.\/}(1997){\it Large, Danabasoglu, Doney, and
  McWilliams\/}}]{Large_jpo_1997}
Large, W.~G., G.~Danabasoglu, S.~C. Doney, and J.~C. McWilliams, Sensitivity to
  surface forcing and boundary layer mixing in a global ocean model:
  annual-mean climatology, {\it J. Phys. Oceanogr.\/}, {\it 27\/}, 2418--2447,
  1997.

\bibitem[{{\it Large et~al.\/}(2000){\it Large, Danabasoglu, McWilliams, Gent,
  and Bryan\/}}]{Large_jpo_2000}
Large, W.~G., G.~Danabasoglu, J.~C. McWilliams, P.~R. Gent, and F.~O. Bryan,
  Equatorial circulation of a global ocean climate model with anisotropic
  horizontal viscosity, {\it J. Phys. Oceanogr.\/}, 2000, in press.

\bibitem[{{\it Matsumoto et~al.\/}(2004)}]{Matsumoto_grl_2004}
Matsumoto, K., et~al., Evaluation of ocean carbon cycle models with data-based
  metrics, {\it Geophys. Res. Lett.\/}, {\it 31\/}, 2004, l07303,
  doi:10.1029/2003GL018970.

\bibitem[{{\it M\"uller et~al.\/}(2005){\it M\"uller, Joos, Edwards, and
  Stocker\/}}]{Mueller_jclim_2005}
M\"uller, S.~A., F.~Joos, N.~R. Edwards, and T.~F. Stocker, Water mass
  distribution and ventilation time scales in a cost-efficient 3-dimensional
  ocean model, {\it J. Clim.\/}, 2005, submitted.

\bibitem[{{\it Pacanowski and Griffies\/}(1998)}]{Pacanowski_1998}
Pacanowski, R.~C., and S.~M. Griffies, Mom 3, version 1: Documentation, user's
  guide and reference manual, {\it GFDL Ocean Technical Report 3.4\/},
  NOAA/Geophys. Fluid Dyn. Lab., Princeton, NJ, 1998.

\bibitem[{{\it Smith\/}(1992)}]{Smith_1992}
Smith, R.~L., Coastal upwelling in the modern ocean, in {\it Upwellng Systems:
  Evolution Since the Early {M}iocene\/}, edited by C.~P. Summerhayes, W.~L.
  Prell, and K.~C. Emeis, vol.~64, pp. 9--28, Geological Society Special
  Publications, London, 1992.

\bibitem[{{\it Stammer et~al.\/}(2004){\it Stammer, Ueyoshi, K\"ohl, Large,
  Josey, and Wunsch\/}}]{Stammer_jgr_2004}
Stammer, D., K.~Ueyoshi, A.~K\"ohl, W.~G. Large, S.~A. Josey, and C.~Wunsch,
  Estimating air-sea fluxes of heat, freshwater, and momentum through global
  ocean data assimilation, {\it J. Geophys. Res.\/}, {\it 109\/}, 2004,
  doi:10.1029/2003JC002082.

\bibitem[{{\it Stone\/}(1972)}]{Stone_jatmsci_1972}
Stone, P., A simplified radiative-dynamical model for the static stability of
  rotating atmospheres, {\it J. Atmos. Sci.\/}, {\it 29\/}, 405--418, 1972.

\bibitem[{{\it Visbeck et~al.\/}(1997){\it Visbeck, Marshall, Haine, and
  Spall\/}}]{Visbeck_jpo_1997}
Visbeck, M., J.~Marshall, T.~Haine, and M.~Spall, On the specification of eddy
  transfer coefficients in coarse resolution ocean circulation models, {\it J.
  Phys. Oceanogr.\/}, {\it 27\/}, 381--402, 1997.

\end{thebibliography}


\end{article}
\newpage


\end{document}
