DRAFT
How to prepare FLEXPART input data?
How to run FLEXPART?
To run a FLEXPART simulation you need to use the FLEXPART Run icon.The simulation itself requires:
- input meteorological fields
These can be generated for FLEXPART using the FLEXPART Prepare icon or with an external application. - the FLEXPART executable
At ECMWF it is centrally installed and does not need to be specified for FLEXPART Run. For a custom-build executable or at other sites please follow the instructions in FLEXPART setup. - some FLEXPART resources
FLEXPART needs a set of files to carry out a simulation: IGBP_int1.dat, OH_7lev_agl.dat, surfdata.t, surfdepo.t. At ECMWF these are centrally installed and do not need to be specified for FLEXPART Run. At other sites please follow the instructions here. - setting the SPECIES to be released
The species we can use in a FLEXPART simulation must be defined by a set of ASCII files. See details about their usage here. - specifying the releases
- defining the run conditions
- the path to the output files
Metview runs FLEXPART in a temporary folder then converts the results and copies them into this folder. FLEXPART outputs can be large so take it into account when selecting this path.
How to specify the FLEXPART executable?
How to define the releases?
A
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The macro code,
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rel_volcano = flexpart_release(
name : "REL 1",
starting_date : 0,
starting_time : 15,
ending_date : 2,
ending_time : 12,
area : [63.63,-19.6,63.63,-19.6],
top_level : 9000,
bottom_level : 1651,
particle_count : 10000,
masses : 100
) |
The location of the FLEXPART executable and that of some other files/directories have to be specified for Metview. These locations can be defined either through a set of Metview environment variables or via parameters in the FLEXPART Run icon (these latter take precedence). The table below summarises what actually is needed to set for Metview.
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The directory containing the following files:
- IGBP_int1.dat
- OH_7lev_agl.dat
- surfdata.t
- surfdepo.t
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These files are distributed in the FLEXPART source inside folder option
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A set of species are distributed in the FLEXPART source inside folder option/SPECIES
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A case study
In this case study will run FLEXPART to simulate the imaginary eruption of the Icelandic volcano Eyjafjallajökull.
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First start Metview; at ECMWF, the command to use is metview (see Metview at ECMWF for details of Metview versions). You should see the main Metview desktop popping up.
You will create some icons yourself, but some are supplied The icons you will work with are already prepared for you - please download the following file:
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and save it in your Alternatively, if at ECMWF then you can copy it like this from the command line: |
You should now (after a few seconds) see a flexta flexpart_tutorial folder. You will work in this folder so Please open it up.
The input data
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Running a forward simulation
Enter folder 'fwd'.
We will run FLEXPART to simulate the release of SO2 from the Icelandic volcano Eyjafjallajökull.
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Since the output GRIB files cannot be handled by Metview's standard Grib Filter icon because (due to the local GRIB definitions we use). Therefore a set of Metview Macro Library Functions were developed to deal with the FLEXPART grib files. Please look into the visualisation macros to see how to use them. The most important Metview Macro Library Functions are as follows:
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Forward simultaions
Fields
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