Many people have been giving important impulses to the development of GOTM.
The first lines of the first PASCAL code have been programmed in late 1992
by Hans Burchard as part of a Ph.D. project at the
Institute of Oceanography at the University of Hamburg, Germany,
under the supervision of Jürgen Sündermann and Helmut Baumert.
This was the basis for a one-dimensional water column model
for simulating the so-called FLEX'76 data (see Burchard and Baumert, 1995),
a two-dimensional channel model (Burchard and Baumert, 1998), and
a three-dimensional shallow water model (Burchard, 1995).
Further substantial advice for these modelling activities came
also from Eckard Kleine (Bundesamt für Seeschiffahrt und Hydrographie,
Hamburg, Germany) who together with Helmut Baumert had
a long time experience in turbulence modelling.
October 18-22, 1999 in Ispra, Italy for the CARTUM autumn school This
shows the still small GOTM developers group with Karsten Bolding, Manuel
Ruiz Villarreal, Hans Burchard and Pierre-Philippe Mathieu.
A strong motivation for extending the model code (which at that stage only
included the k-epsilon model) came in 1995 from George Mellor (Princeton
University, New Jersey) who provoked with the statement that he never
saw a k-epsilon model (in contrast
to the Mellor-Yamada model) reproducing the Monin-Obukhov similarity theory.
In an effort together with Ole Petersen (International Centre of Computational
Hydrodynamics, Hørsholm, Denmark) the equivalence of the k-epsilon and
the Mellor-Yamada models under certain circumstances and thus the successful
reproduction of the Monin-Obukhov similarity theory could be demonstrated
by Burchard et al. (1998) and Burchard and Petersen (1999).
Numerical stability problems occurred when the water column model (now already
with a switch for choosing either the k-epsilon or the Mellor-Yamada model)
was transferred to FORTRAN in late 1996. It was Boris Kagan (Shirshov
Institute of Oceanology, St. Petersburg, Russia) who insisted that
oscillations in the turbulent macro length scale under very small stable
stratification are numerical artifacts and therefore unacceptable.
The solution to that problem was finally to use double instead of
single precision for the calculations.
In a cooperation with Nadia Pinardi and Sergio Castellari
(Istituto per lo Studio delle Metodologie Geofisiche Ambientali, Bologna,
Italy) during 1997 and 1998, the experiences made with this FORTRAN code
were incorporated into a version of the Modular Ocean Model (MOM,
Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey) for
calculating the general circulation and convective events in the
Mediterranean Sea (Castellari et al., 1999).
During the same years, the turbulence model was under strong criticism
from Walter Eifler and Adolf Stips (Joint Research Centre, Ispra, Italy)
when it was inter-calibrated with in-situ measurements of dissipation
rate in two different estuaries.
During this effort both, the strategies for both, modelling and measurements were
significantly improved. However, discrepancies remained and the discussion is
still going on (Burchard et al., 1999).
The idea of GOTM, as it is presented here, was born in spring 1998, when
Karsten Bolding joined the development.
It was a major effort to collect the many different codes
(each set up for only one test case), written in different programming
languages, stored on different computers and merge them together into one
product. In summer 1998, Manuel Ruiz Villarreal joined us on all levels
of GOTM such as internal wave parameterisations, algebraic length scales,
documentation, test cases, graphics, etc.
At this stage, the first version of GOTM was copied to the anonymous-ftp
server of the Institute of Oceanography in Hamburg, Germany on May 1, 1999 as
GOTM1.0.
Later, Pierre-Philippe Mathieu, JRC Ispra, Italy carried out two major
changes which considerably ease the use of GOTM. A general tracer
routine (yevol.f) has been created for easy addition of further tracer
equations such as biological modules. Secondly, a graphical output for the
Grid Analysis and Display System (GrADS) was added, which allows for a
quick analysis of simulation results. The namelists for the scenarios did
not have to be changed. Therefore this new version was called GOTM1.1 and
copied to the anonymous-ftp server on July 4, 1999. Such, Pierre-Philippe
became GOTM author no. 4.
