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The EMEP models have been instrumental to the development of air quality policies in Europe since the late 1970s, mainly through their support to the strategy work under the Convention on Long-range Transboundary Air Pollution. In the 1990s the EMEP models became also the reference tools for atmospheric dispersion calculations as input to the Integrated Assessment Modelling, which supports the development of air quality polices in the European Union. While results from the EMEP models have been available to the international community through the EMEP programme for many years, the model code of one of the EMEP chemical transport models was made publicly available only recently.

Through this web page the latest EMEP/MSC-W model version used for the EMEP status reporting of the year 2014 - rv4.5 - is released, together with a set of input data and a full year model results for the year 2012, under GPL license v3.

OpenSource rv4.5 (201409).

Previous releases (YYYYMM - date of release):

Please read the updated EMEP MSC-W model User Guide available for each release on respective ftp site.

The EMEP/MSC-W model is designed to calculate air concentrations and deposition fields for major acidifying and eutrophying pollutants, photo-oxidants and particulate matter. The present release of the model is intended to:

facilitate insight in the model assumptions, the parametrisation used, the requirements for input data and the actual model code
encourage dialogue and collaboration with the modelling community
allow individual model runs and insight on how to run different scenarios

Questions on the EMEP model can be addressed to emep.mscw@met.no. Support to the user community will be developed here with your contribution. Please let us know what your needs for information are.

The EMEP/MSC-W model is a chemical transport model developed at the Meteorological Synthesizing Centre - West (MSC-W) at the Norwegian Meteorological Institute (met.no). The EMEP model is a limited-area, terrain following sigma coordinate model designed to calculate air concentration and deposition fields for

acidifying and eutrophying compounds (S, N)
ground level ozone (O3)
particulate matter (PM2.5, PM10).

as well as their long-range transport and fluxes across national boundaries (Transboundary air pollution). A history of the development of the EMEP model can be found at http://www.emep.int/models.

Model Description

The EMEP MSC-W chemical transport model – technical description D. Simpson, A. Benedictow, H. Berge, R. Bergström, L. D. Emberson, H. Fagerli, C. R. Flechard, G. D. Hayman, M. Gauss, J. E. Jonson, M. E. Jenkin, A. Nyíri, C. Richter, V. S. Semeena, S. Tsyro, J.-P. Tuovinen, Á. Valdebenito, and P. Wind Atmos. Chem. Phys., 12, 7825-7865, 2012 http://www.atmos-chem-phys.net/12/7825/2012/acp-12-7825-2012.html

To compile the EMEP model you need:

Fortran 95 compiler
NetCDF Library (>4.1.3)
MPI Library (>1.0)

It is necessary to compile with double precision reals (8 bytes reals). The program has been used on computers ranging from a Linux laptop to supercomputers (Itanium2 cluster, Intel Xeon cluster, Cray XT4, IBM power5+). It is compatible with all compilers tested so far: Intel, PGI, gfortran, XL fortran. A Makefile is included, the path to netcdf (INCL and LLIB) has to be adapted to your machine, and to the fortran compiler (F90) and flags (F90FLAGS) to the compiler you are using.

The code has been tested with 1 to 1024 CPUs, and scales well (for large grids). If only one CPU is used 1-2 GB memory is required. If more than one, for example 64 CPUs are used, 200 MB of memory per CPU is enough (in the case of a 132 X 159 grid size). For runs on more than 32 CPUs, a fast interconnect is recommended (infiniband for example), for smaller runs, gigabit ethernet is sufficient. It takes ~3.5 hrs on 64*Xeon X5355 (2.66GHz) for a 1-year simulation.

When downloading input data in order to do a “base run” please make sure that there are 35 Gb disc space available, especially due to large meteorology input files. The model can be run for shorter periods, users can download meteorology for only the period they are interested in, plus one day.

It is recommended to register as an EMEP User before you start downloading any input data, model code or model results. Please read through the “Terms of use” and “Privacy Policy” thoroughly before you agree to the terms presented there.

Your registration gives you access to the EMEP forum where questions and answers on the model code and its uses are to be exchanged. Support to the user community of the EMEP model will develop here with your contribution.

The information given about your e-mail address in this registration is not to be distributed, but it is stored in a database only available to the administrator of this EMEP Forum. The database can be useful for the EMEP/MSC-W group if, for instance, special information about the EMEP/MSC-W model is to be distributed to the Users.

You are recommended to register as an EMEP User and read all chapters of the EMEP/MSC-W model User Guide before you start downloading data from the following links:

a complete set of input data to allow for model runs for year 2011
the open source model code of the EMEP/MSC-W model version rv4_4
model results for the year 2010 for comparison of a successful run

A complete set of input files is provided in tar files available from the EMEP/MSC-W Open Source ftp sites: met2011 and input_data_2011 to allow model runs for the year 2011 (also data for 2010 is available as well).

IMPORTANT: The input data available in this ftp site should be appropriately acknowledged when used for model runs. If nothing else is specified according to references further in this chapter, please acknowledge EMEP/MSC-W in any use of these data.

The standard input files for the EMEP model are provided in two different formats, netCDF or ASCII. We presently follow as much as possible the netCDF CF1.0 conventions for both input and output data. More details about the input files are described in Chapter 2 of the EMEP/MSC-W model rv4.4 User Guide.

The EMEP/MSC-W model code version rv4.4 is archived into a tar file available from the EMEP Open Source ftp site model_code. The tar file includes the model source code, a run script, the namelist file, a makefile and a copy of the gpl license. More details about the model code and how to submit a model run are described in the EMEP MSC-W model rv4.4 User Guide.

The EMEP/MSC-W model is very flexible with regard to the horizontal resolution and in 2008 the EMEP domain was extended to include EECCA countries. The current version, and the provided gridded input data, have a horizontal resolution of 50×50 km2 (at 60°N) and are defined on a polar stereographic projection.

A reference run for the year 2011 have been done and the results of this run is available from the EMEP Open Source ftp site model_results_2011 for comparison for new users of the EMEP/MSC-W model.

The main output files are in netCDF (netCDF CF1.0 conventions) format and some additional output files are in ASCII format. More details about the output files are described in Chapter 3 of the EMEP MSC-W model User Guide

The EMEP/MSC-W model is validated and reported to the Cooperative Programme for Monitoring and Evaluation of the Long-range Transmission for Air Pollutants in Europe (EMEP) each year by the EMEP/MSC-W group. The reports can be found under the following links: