Status report on NO COMMENTS, December 1999
This status report is based on input from Bertil Håkansson (SMHI), Ingerid Fossum, Harald
Engedahl and Lars Petter Røed (DNMI), and Henrik Søiland and Einar Svendsen (coordinator)
(IMR).
NO COMMENTS (Nordic COMmunity Model for Environmental Tasks in the Seas) was created as
a project during a meeting in Bergen 5-6 November 1998 with participants from Denmark,
Sweden, Finland and Norway. During the first phase of the project, the task were given to the
Swedish Meteorological and Hydrological Institute (SMHI), the Norwegian Meteorological
Institute (DNMI) and the Norwegian Institute of Marine Research (IMR), to continue the work on
developing first operational versions of coupled 3-dimensional circulation and primary production
models for the North Sea and the Baltic.
The goal of the project is: To develop an operational modeling tool for environmental
management and planning in the Baltic and the North Sea.
During 1999 SMHI has upgraded the coupled 3D physical-biochemical model system (HIROMBSCOBI) from the regional scale to cover the Baltic Sea, Kattegat and Skagerrak. An earlier and
regional version of the system has been presented in Marmefelt et al. (1999). A hydrological model
covering the drainage area of the ocean model area is coupled to the system, giving input on fresh
water and nutrients on a daily basis. In addition atmospheric load data from the atmospheric
MATCH model is used. Also processes linked to oxygen deficiency has been improved, in order to
cover deep water areas where oxygen concentrations are low which feed back to chemical
processes. The whole system is now ready for validation and evaluation. The year 1997 is selected
as the test year of the system.
During 1999 IMR has continued the work with improving and validating the 3D physical-chemicalbiological model system NORWECOM covering the greater North Sea (Søiland and Skogen, In
press) and Skagerrak. The latest version has also been implemented and tested in a domain with 4
km resolution covering the west coast of Denmark, Kattegat, Skagerrak and the Norwegian coast
north to Stad.
In April/May high concentrations of nitrogen nutrients were observed in Skagerrak. This prompted
action at IMR and steps were taken to run NORWECOM at IMR if a harmful algae bloom was to
occur. However such a bloom did not develop, probably partly because the weather conditions were
windy and cloudy. In the preparations contact was established with the Global Runoff Data Center
in Koblenz Germany, and up to date runoff data from the German rivers was obtained.
One major task at the DNMI has in 1999 been to establish a coupled physical, chemical and
biological model system based on the daily operational circulation model (here called TOM) and
NORWECOM, and utilizing the infrastructure for producing forecasts on a routine basis at DNMI.
For this purpose the chemical and biological module (CBM) of NORWECOM has been transferred
to DNMI and coupled to TOM.
The circulation models used in NORWECOM and TOM are very similar. However, TOM has been
implemented to be a part of the daily operational production line based on output from the
meteorological model suite at DNMI. NORWECOM has mainly been used in research and to
address management issues in a hindcast mode. Thus the implementation of the models are quite
different and in order to incorporate the CBM part of NORWECOM in the daily operational runs at
DNMI it has been necessary to make many changes. This includes changes to how the boundary
conditions and river loads are treated in the model. Another important requirement for daily
operational use, is the possibility to restart the model system (hot start). Before the coupled system
could be tested for operational use, a model code had to be implemented that reads from and writes
to a restart file containing chemical-biological variables.
An important milestone was reached at May 9 when a coupled physical, chemical-biological model
was included in the daily operational routine at DNMI (that is; daily forecast automatically on a
routine basis). The model covered the large domain on a grid with 20 km mesh size. The results
were transferred on daily basis to IMR. This was mainly to verify the implementation and
modifications made in the CBM, and should be regarded as a ``technical'' test.
During the same period the work of testing the model system on a smaller model domain with
better resolution (4 km) covering Skagerrak and Kattegat continued. The fine scale model was
nested into the large scale model. As mentioned above the results in the large scale North Sea
model were not satisfactory. Some of the errors were detected during the testing of the fine scale
model and these will be corrected before operational model runs are started early next year. The
operational runs of the 20 km model were stopped at October 1, 1999.
Routines to transfer and evaluate the results from the operational runs performed by DNMI (using
the chemical-biological module of NORWECOM) have been established. The results from these
runs have been evaluated at IMR. However the results have not been satisfactory, and the work with
detecting and correcting the causes of these errors is ongoing.
References:
Engedahl, H. (1995) Implementation of the Princeton Ocean Model (POM/ECOM3D) at
Norwegian Meteorological Institute. DNMI Research Report No. 5, Norwegian Meteorological
Institute, 40s.
Marmefelt E., Arheimer, B & J. Langner 1999. An integrated biogeochemical model system for the
Baltic sea. Hydrobiologia 393, 45 -56.
Skogen, M. D. (1993) A User's guide to NORWECOM. Rapport fra Senter for Marint Miljø 1993,
6.
Søiland, H. and Skogen, M., In press. Validation of a 3-D biophysical model using nutrient
observations in the North Sea. ICES Journal of Marine Research.
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