April 2020

General informations
This program is dedicated to plot backtrajectories using WRF or CHIMERE simulation outputs. The user can define or locations and one time comtained in the simulation file. A large number of trajectories are launched backward and a random function is applied when atmosphere is turbulent. The ensemble of all trajectories represents all possible origins of the air mass finally sampled at the starting point. To run this code, several softwares are required:

  1. a fortran compiler
  2. NetCDF libraries
  3. nco
Two graphical sofwares can be used (or replaced) to plot the results:
  1. GMT plotting sofware (for the maps)
  2. XMGRACE plotting sofware (for the altitudes of trajectories)
Results are written in ascii files. Two main codes have to be edited and modified:
    before compilation, we need to know the local user's environment. If you are already using chimere, you just have to specify the chimere path:
    If you are not using chimere, you have to build a '' like file following the example proposed here: mychimere.sh_example. The same for the Makefile.hdr_example file, to copy after changes in 'Makefile.hdr'.
    The main script for backplumes calculations. Some options are mandatory some others are optional. Mandatory:
    # Where are the files of the simulation to use
    # What is the name of domain?
    # Where to store the output figures and intermediary files?
    All others options are optional and correspond to the number of processors you want to run the code, the number of trajectories per plot, the filtering of the result, the kind of interpolation etc.
If you want to use GMT and the prepared script, you just have to launch the script: ./ Note that you have to edit this script to specify the frame size of the region to plot (longitude and latitude, min and max).

The code is freely available here: code TGZ archive


  1. Mailler S., L. Menut, A. G. Di Sarra, S. Becagli, T. Di Iorio, B. Bessagnet, R. Briant, P. Formenti, J.F. Doussin, J. L. Gomez-Amo, M. Mallet, G. Rea, G. Siour, D. M. Sferlazzo, R. Traversi, R. Udisti, and S. Turquety, 2015, On the radiative impact of aerosols on photolysis rates: comparison of simulations and observations in the Lampedusa island during the CharMEx/ADRIMED campaign, Atmos. Chem. Phys., 16, 1219-1244, doi:10.5194/acp-16-1219-2016
  2. Bessagnet B., L.Menut, and M.Beauchamp, A N-dimensional Fortran Interpolation Program for Geophysics Sciences - Application to a back-trajectories program using CHIMERE or WRF outputs, GMDD, 2020.

Questions and Acknowledgments

  • Questions:
    please send an e-mail to Laurent Menut []
  • Acknowledgments:
    if the program is a key point for your study, you are invited to propose co-authorship, else you can add this sentence in acknowledgments: "Authors acknowledge Laurent Menut and Bertrand Bessagnet for the development and sharing of the backplumes program available at".