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Black and Bloom use of FLEXPART

Our work has revolved around the FLEXPART software (, and has included compiling, installing and running the software, as well as retrieving input data for use with the model.

FLEXPART (“FLEXible PARTicle dispersion model”) is a Lagrangian transport and dispersion model suitable for the simulation of a large range of atmospheric transport processes.

FLEXPART has been installed on Linux systems within the School as well as on the ARC3 and ARC4 systems.

On the ARC systems, FLEXPART has been compiled with various compilers and MPI libraries, and can be accessed via the CEMAC modules:

FLEXPART can use GFS data as input, as well as ECMWF ERA-interim and ERA5 data. Most of the work we have done has been with the ERA5 input data.

Retrieving the input data is done using a special flex_extract tool, created by the FLEXPART developers.

This tool retrieves the data from ECMWF using a Python interface to their API (ecmwfapi for ERA-interim, cdsapi for ERA5), and our work has included both downloading data for researchers to use, and advising researchers how to download the data for themselves.

The ERA5 data can take some time to download (2 to 3 days to retrieve one month of data), and the options used with the data retrieval tool can effect the time taken to download the data, so some work was done to try and find a set of parameters which worked reasonably well.

Where FLEXPART has been run by CEMAC, the researchers selected the required parameters, and the jobs were then set up and run on the ARC systems. Sometimes, this has required queueing thousands of jobs at a time.

Some example of scripts used can be found here:

Simple plots and animations of the output data have also been created, to allow the researchers to take a quick look at the results and inform decisions o any parameters which may need to be adjusted.

Some sample images of output


figure 1a


figure 1b