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The FLEXPART environment

At ECMWF version 902 of FLEXPART is centrally installed on ecgate and on some internal Linux-based systems. On these systems Metview is configured to pick up the FLEXPART location automatically via these environment variables:

  • MV_FLEXPART_EXE_PATH: defines the FLEXPART executable
  • MV_FLEXPART_RESOURCES_PATH: specifies the directory containing the following files IGBP_int1.dat, OH_7lev_agl.dat, surfdata.t and surfdepo.t
  • MV_FLEXPART_SPECIES_PATH: specifies the directory containing the species

Hard-coded parameters

Some of the important FLEXPART parameters cannot be specified at run time but are hard-coded in the source. The FLEXPART installation at ECMWF uses the following set of hard-coded parameters:

DescriptionValueParameter in sourceSource file
ecgatelinux desktop
Maximum number of grid points in E-W (input grid)


Maximum number of grid points in N-S (input grid)361361nymaxpar_mod.f90
Maximum number of model levels (input grid)138138
Maximum number of species66maxspecpar_mod.f90
Maximum number of particles20000002000000maxpartpar_mod.f90
Maximum number of age classes1010maxageclasspar_mod.f90
Maximum number of receptor sites200200maxreceptorspar_mod.f90
Maximum number of output grid nests00maxnestspar_mod.f90


compiler: gfortran

compilation options:

-O3 -m64 -mcmodel=medium -fconvert=little-endian -frecord-marker=4

Necessary code modifications

To make FLEXPART work at ECMWF the following modifications had to be made in the source code:

1. Resolve type mismatch in err.f90 with newer gfortran compiler: see flextra ticket49

This involved the modification in err.f90 of line 106 and 111

and line 140 and 145 as well.

2. Make FLEXPART work for 137 model levels

In par_mod.f90 line 125 had to be modified:

Additional code modifications

We changed the code to increase the maximum value of some parameters.

1. Increase maximum number of age classes

In par_mod.f90:

2. Increase maximum number of species

In par_mod.f90:


  1. can we installed the flexpart by apt-get to use it with metview? or do we need to download the package from flexpart website and modify manually?

  2. Hello @ann sal ,

    Could you create a ticket in our Support Portal please, then we can track and respond better.