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How to specify the FLEXPART executable?
How to define the
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The species (chemical elements) released during a simulation are specified as integer numbers in the Release Species parameter in FLEXPART Run. The integer ID of the individual species are taken from the name of the species definition files.These have to be located in the directory defined
- via the User Species Path parameter in FLEXPART Run
- or if it is left blank (this is the default value) Metview will use the MV_FLEXPART_SPECIES environment variable.
The species distributed with FLEXPART
Folder option/SPECIES in the FLEXPART distribution contains a default set of species definitions. Here each species is represented by a file called SPECIES_NNN , where NNN is the integer ID of the given species.The table below summarises what species are available:
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SPECIES_001
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SPECIES_002
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SPECIES_024
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SPECIES_009
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SPECIES_019
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SPECIES_020
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At ECMWF
The species are located in the directory specified by environment variable MV_FLEXPART_SPECIES. The contents of this directory is the same as that of folder option/SPECIES in the FLEXPART distribution.
At other sites
Instructions to setup the species path can be found here.
Using your own definitions
If you want create your own species definition you need make a copy of this directory and add your own species to it. Then set the path in User Species Path so that FLEXPART could pick up your definitions.
How to define the releases?
A release is defined with the FLEXPART Release icon. In our example the release is defined with iconshappens at a point between 1651 and 9000 m. The emitted mass is 100 kg.
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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 ) |
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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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In this case study will run FLEXPART for an to simulate the imaginary eruption of the Icelandic volcano eruption happened in 2012Eyjafjallajökull.
Preparations
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.
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You should now (after a few seconds) see a flexta_tutorial folder. You will work in this folder so open it up.
The input data
The input data is already prepared for you and is located in folder 'Data'. The You will find a FLEXPART Prepare icon and its Macro equivalent can be found in the Prepare folder.
Run a forward simulation
The fwd_conc FLEXPART Run icon defines the forward simulation. It requires the release description that we define with the vol_release icon. The macro geas like this:
that was used to generate the data in folder 'Prepare'. The corresponding macro code can also be found there.
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You do not need to run the data preparation. However, if you wish to do so please note that it requires MARS access and you must set the Output Path parameter accordingly. |
Running a forward simulation
Enter folder 'fwd'
We will run FLEXPART to simulate the release of SO2 from the Icelandic volcano Eyjafjallajökull.
The simulation is defined via the 'fwd_conc' FLEXPART Run and the 'rel_volcano' FLEXPART Release icons, respectively. Both these are encompassed in the 'fw_cond.mv' Macro. For simplicity will use this macro to show the simulation in detail.
First we define the release like this: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
) |
This says that the release will happen over a 45 h period between heights 1651 and 10000 m at the location of the volcano and we will release 100 kg worth of particles.
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Please note that
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The actual simulation is carried out by calling flexpart_run():
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#Run flexpart (asynchronous call!) r = flexpart_run( output_path : "result_fwd_conc", input_path : "../data", starting_date : 20120517, starting_time : 12, ending_date : 20120519, ending_time : 12, output_flux : "on", output_trajectory : "on", output_area : [40,-25,66,10], output_grid : [0.525,0.525], output_levels : [500,1000,2000,3000,4000,5000,7500,10000,15000], release_species : 8, receptors : "on", receptor_names : ["rec1","rec2"], receptor_latitudes : [60,56.9], receptor_longitudes : [6.43,-3.5], releases : rel_volcano ) print(r) |
Here the actual release species is specified as an integer code (for details about using the species please see here).
Forward simultaions
Fields
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