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%% Abstract
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%% Common part between NEMO-SI3-TOP
``Tracers in Ocean Paradigm'' (\TOP) is the passive tracers engine of
the \NEMO\ ocean model (``Nucleus for European Modelling of the Ocean'').
It is intended to be a flexible tool for studying the on/offline oceanic tracers transport and
the biogeochemical processes (``green ocean''),
as well as its interactions with the other components of the Earth climate system over
a wide range of space and time scales.
\TOP\ is interfaced with the \NEMO\ ocean engine, and,
via the \href{http://portal.enes.org/oasis}{OASIS} coupler,
with several atmospheric general circulation models.
%It also supports two-way grid embedding by means of the \href{http://agrif.imag.fr}{AGRIF} software.

%% Specific part
This component provides the physical constraints and boundaries conditions for
oceanic tracers transport and represents a generalized, hardwired interface toward
biogeochemical models to enable a seamless coupling.
In particular, transport dynamics are supplied by the ocean dynamical core thus
enabling the use of all available advection and diffusion schemes in both on- and off-line modes.
\TOP\ is designed to handle multiple oceanic tracers through a modular approach and
it includes different sub-modules: ocean water age, inorganic carbon (CFCs) \& radiocarbon (C14b),
built-in biogeochemical model (PISCES), and prototype for user-defined cases or
coupling with alternative biogeochemical models (\eg \href{http://www.bfm-community.eu}{BFM}).