OPERADAR is developed at CNRM (National Centre for Meteorological Research) to compute synthetic dual-polarization radar variables from model fields in a 3D grid.
The computed variables include reflectivity
It is adapted to read AROME and MesoNH atmospheric model files, and the available options (mass-density relations, particle size distributions) are consistent with the microphysics options currently available for these models.
OPERADAR is used for research applications, mainly for the evaluation of AROME and MesoNH microphysics schemes in the polarimetric radar space. It currently requires a repository of lookup tables. These tables contain the scattering coefficients to compute the polarimetric variables, either in the Rayleigh or Mie scattering regime (with the T-matrix method).
------- NEW SINCE JUNE 2025 ! -------
OPERADAR software now includes an executable to generate the lookup tables. The scattering coefficients stored in the tables are computed both in the Rayleigh approximation and using the T-matrix method (see Mishchenko and Travis 1994).
- Model file (
.fafor AROME files or.ncfor MesoNH) - Configuration file
- Lookup tables (created beforehand with the table generator executable).
- For colleagues at CNRM, the default configuration of the tables can be found on HPC at
/home/augros/TmatCoefInt_SCXKaW/
- X/Y grid horizontal coordinates (1D)
- model pressure levels vertical coordinates (1D)
- latitude/longitude fields (2D)
- dual-pol variables :
$Z_{H}$ ,$Z_{DR}$ ,$K_{DP}$ ,$\rho_{HV}$ (3D) - specific attenuation :
$A_{H}$ ,$A_{v}$ (3D) - temperature, altitude, contents and concentrations fields (3D)
- dataset attributes such as the horizontal resolution, the options used to compute the mixed-phase or simulate the radar data.
Install operadar in a dedicated virtual environment: Installation-tutorial.
- To work properly, lookup tables should be generated before running
operadar(unless you have a direct access to the tables). Steps to create the tables are available in Generation of the lookup tables.
--> If you already have access to the tables, you may skip this step. - A configuration file is red by
operadarto compute the polarimetric fields, according to your chosen parameterization. See Simulation configuration for extended explanations. - Finally, a shell executable is provided to launch the forward operator for one file at a time. However,
operadarcan be used within other algorithm, to loop on multiple files and eventually with varying configurations over files that share certain common parameters. Explanations are in Execution of the forward operator
If you wish to contribute to the project, first, fork the code to create your own copy of the project (see https://docs.github.com/en/get-started/exploring-projects-on-github/contributing-to-a-project#creating-your-own-copy-of-a-project).
If you use operadar in a published work, please cite the following papers:
- Augros, C., Caumont, O., Ducrocq, V., Gaussiat, N., & Tabary, P. (2016). Comparisons between S, C, and X band polarimetric radar observations and convective-scale simulations of HyMeX first special observing period. Quarterly Journal of the Royal Meteorological Society, 142, Issue S1, 347–362. https://doi.org/10.1002/qj.2572
- David, Cloé, et al. “Improved Simulation of Thunderstorm Characteristics and Polarimetric Signatures with LIMA Two-Moment Microphysics in AROME.” Atmospheric Measurement Techniques, vol. 18, no. 15, Aug. 2025, pp. 3715–45. Copernicus Online Journals, https://doi.org/10.5194/amt-18-3715-2025.
You should also cite the Fortran 77 T-matrix code that is employed to generate the scattering coefficients with the T-matrix method:
- Mishchenko, M. I., & Travis, L. D. (1994). T-matrix computations of light scattering by large spheroidal particles. Optics Communications, 109(1), 16–21. http://www.sciencedirect.com/science/article/pii/0030401894907315
- After installing environment, run:
python -c "import operadar; import epygram; print('operadar OK, epygram', getattr(epygram,'__version__','unknown'))"Before making changes to the project, you should create a new branch and check it out. Try to be self explanatory for the name of the branch. Then, install operadar as a package with the aforementioned procedure. To ask for integration of your modifications, please open a pull request following https://docs.github.com/en/get-started/exploring-projects-on-github/contributing-to-a-project#making-a-pull-request.
This software is governed by the open-source CeCILL-C license under French law, cf. LICENSE.txt. Downloading and using this code means that you have had knowledge of the CeCILL-C license and that you accept its terms.