GOTM is the abbreviation for `General Ocean Turbulence Model'. It is a
one-dimensional water column model for the most important hydrodynamic
and thermodynamic processes related to vertical mixing in natural
waters. In addition, it has been designed such that it can easily be
coupled to 3-D circulation models, and used as a module for the
computation of vertical turbulent mixing. The core of the model
computes solutions for the one-dimensional versions of the transport
equations of momentum, salt and heat. The key component in solving
these equations is the model for the turbulent fluxes of these
quantities. The strength of GOTM is the vast number of well-tested
turbulence models that have been implemented in the code. These models
span the range from simple prescribed expressions for the turbulent
diffusivities up to complex Reynolds-stress models with several
differential transport equations to solve. Even though, evidently, not
all turbulence models published in oceanography could be implemented,
at least one member of every relevant model family can be found in
GOTM: empirical models, energy models, two-equation models, Explicit
Algebraic Stress Models (EASM), and K-profile parameterisations (KPP).
Besides the classical combination of the hydrodynamic and turbulent part
of the model, GOTM has been growing considerably with the years, and
new parts have been developed. Sediment transport and the dynamics of
sea grass have been added, state-of-the-art numerical schemes have been
implemented, and an environment for the assimilation of data and the
computation of atmosphere-ocean interactions exists now. In addition,
there is a number of scientific research groups that adopted GOTM for
their own projects. Even though the modules developed by these groups
(biological and bio-geochemical components, air-sea interaction
modules, plotting routines, etc) are not part of the core structure of
GOTM, as downloadable from this web site, they are in most cases
available directly from these groups. In that sense, GOTM is an
integrated, community based software environment for an almost
unlimited range of applications in geophysical turbulence modelling.
The idea behind GOTM
Computer codes similar to pieces of GOTM can be found at many
scientific institutions. However, different researchers have different
goals. Some are interested in the development of turbulence models,
others in oceanic applications of these models, and yet others want to
compare the effects of different turbulence models on different
processes in the ocean or in lakes. The attempt to use one of their
specialised programs for one's own project resulted in many cases in
spending weeks of work for deciphering non-documented FORTRAN lines,
scattered with pre-historic fragments of code from more or, in some
cases, less talented programmers. Additional time had to be spend for
providing components for atmospheric forcing, etc, before the own
research project could finally be attacked.
To overcome these problems, the GOTM project was initiated, its purpose
being twofold. First, GOTM should provide an integrative environment
for all researchers interested in the application
of a turbulence model in studies of oceanic processes. Such a software
should contain a core part for solving transport equations of mean and
turbulent quantities, but equally well routines to compute the
atmosphere-ocean fluxes from meteorological or measured data, including
routines to interpolate and manipulate them. Second, however, GOTM
should also be a research tool for those interested in the development of turbulence models
and numerical algorithms. This implies that GOTM should always contain
the state-of-the-art models and algorithms in these disciplines. The
current version of GOTM was developed under these premises.
In both cases, a detailed and comprehensible documentation is crucial,
and we spent a lot of effort to come close to this goal. All
methods and models embedded in GOTM can be traced back to scientific
publications, a key requirement for the scientific use of a program.
Also, we took great care to make the FORTRAN95 code as safe, easily
understandable, and extensible, as possible.
Acknowledgements
The developer's team
of GOTM is grateful to the former members of the team for
their persisting cooperation. These are particularly members from the
very first days of GOTM which took place at the Joint Research Centre
in Ispra (Italy) in 1998: Manuel Ruiz Villarreal who worked after the
Ispra time in Santiago de Compostela (Spain), Lisboa (Portugal),
Hamburg (Germany), and Warnemünde (Germany) before he moved back to
his home country for working in A Coruna (Spain). Pierre-Phillipe
Mathieu, who went to Reading (U.K.) for sometime before he arrived in
Frascati (Italy). We further want to acknowledge those of the
almost 200 subscribed users of GOTM from all over the world who helped
us to improve GOTM, reported bugs, and motivated us to go on with this
zero-budget project. It was also the important role which GOTM
played in several projects, mostly funded by the European Commission,
which helped a lot to maintain GOTM.
These projects were MAS3-CT96-0053 ('PHASE'), MAS3-CT96-0051 ('MTP II-MATER'),
MAS3-CT97-0025 ('PROVESS'), EVK3-2001-00144 ('MaBenE')
and especially CARTUM (Comparative Analysis
and Rationalisation of Second-Moment Turbulence Models), a
brainstorming activity (MAS3-CT98-0172), which brought together
turbulence specialists from all over the world. We are finally
grateful to all those other people working on the Public Domain
Software without which a project like GOTM would be unthinkable: LaTeX,
PROTEX, LINUX and many others.
