Documentation

The Unified EMEP model is a chemical transport model developed at the Air Pollution Section at the Norwegian Meteorological Institute (met.no) /Meteorological Synthesizing Centre - West (MSC-W). The Unified EMEP model is a limited-area, terrain following sigma coordinate model designed to calculate air concentration and deposition fields for as well as their long-range transport and fluxes across national boundaries (Transboundary air pollution). A history of the development of the Unified EMEP model can be found here.

The Unified EMEP model code version rv3 was released as open source under the GPL license v3 in February 2008. The release of the code included also a full input data set for 2005 and model results for comparison.


Model Description

A detailed documentation of the Unified EMEP model is available online (a html file). The references to this documentation are given below:

    D. Simpson, H. Fagerli, J.E. Jonson, S. Tsyro, P. Wind, and J. -P. Tuovinen, Transboundary acidification and eutrophication and ground level ozone in Europe: Unified EMEP Model Description, EMEP Status Report 1/2003 Part I, EMEP/MSC-W Report, The Norwegian Meteorological Institute, Oslo, Norway, 2003.

    H. Fagerli, D. Simpson and S. Tsyro, Transboundary acidification, eutrophication and ground level ozone in Europe, EMEP Status Report 1/2004, Unified EMEP model: Updates, pp.11-18, The Norwegian Meteorological Institute, Oslo, Norway, 2004.



Computer Requirements

To compile the Unified EMEP model you need: It is necessary to compile with double precision reals (8 bytes reals). The program has been tested with PGI 6.0 and Intel compilers on x86 platforms, an Intel compiler on an Itanium2 cluster, and with an XL compiler on a power5+ cluster; examples of Makefiles are provided with the model code source files.

The code has been tested with 1 to 128 CPU, and scales well. If only one CPU is used 1-2 GB memory is required and if more than one for example 32 CPU are used, 200 MB of memory per CPU is enough (in the case of a 170X133 grid size). It takes ∼ 4.5 hrs on 32 Opteron 246 (2GHz) for 1 year.

When downloading input data in order to do a 'base run' please make sure that there are 19 Gb disc space available, especially due to large meteorology input files.



Getting started

It is recommended to read all the chapters of the Unified EMEP model User Guide before you start downloading anything from this EMEP Open Source website.

Please register as an EMEP User on the EMEP Forum before you start downloading the Unified EMEP model code and/or input data. This will give you access to further communication with the developing team and to the section on Questions and Answers.

This is what you need to do before you can do a 'base run' with the Unified EMEP model:

If you have any questions please go to the EMEP Forum after you registered.



Submitting a Run

We provide here detailed information on how to run the regional Unified EMEP model for 3 different types of simulations, namely: Click on the corresponding links to see details of these runs and how to submit such a run. We suggest that users test the 'Base runs' first, which can be done without significant changes in the code itself. One can also use the outputs of such a run in the future as a reference run for the other simulations.

As explained in Chapter 1 of the Unified EMEP model User Guide, once the model tar file is untarred and all the files are located in the directory called Unify/Unimod.rv3/, one can find the run script with name "modrun.pl" in this directory.

"modrun.pl" is a Perl script which governs the compilation of the appropriate "Makefile" and FORTRAN modules. This script should be submitted for run after the necessary modifications are done with respect to the user's demands. The procedure for running the "modrun.pl" script is somewhat different on different computer systems. In the example given below we assume that we submit a run on a Linux cluster.



Visualisation Tools

Visualisation of the data graphically, analyzing the model output and interpret the data are the most important and crucial parts of modelling.

Since the Unified EMEP model is on a polar stereographic projection, some specific graphical packages are more suitable to visualise the model outputs. At met.no, we use the following packages:



EMEP Review

The Unified EMEP model is constantly under revision by the Executive Body for the Convention on Long-range Transboundary Air Pollution (LRTAP). Under the Steering Body to the Cooperative Programme for Monitoring and Evaluation of the Long-range Transmission for Air Pollutants in Europe (EMEP) meetings are arranged like the Task Force on Measurement and Modelling (TFMM) for reviews on the EMEP work (i.e. the Unified EMEP model). You can access the latest review and the review of the Unified EMEP model in 2004 from the following links:



Verification

The Unified EMEP 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: