MPTRAC

MPTRAC designed for studying atmospheric transport processes from regional to global scales. It calculates the motion of large ensembles of air parcels using meteorological fields from global reanalyses and forecasts and provides parameterizations for processes such as turbulent diffusion, convection, sedimentation, chemistry, and deposition.

MPTRAC is used for a wide range of scientific applications, including long-range pollutant transport, volcanic emissions, tracer studies, atmospheric composition research, and studies of transport processes in the upper troposphere and stratosphere. Forward and backward simulations can be performed for both trajectory analysis and particle dispersion applications.

The software is designed for efficient execution on modern high performance computing systems. Hybrid MPI, OpenMP, and OpenACC parallelization enables simulations on systems ranging from individual workstations to large CPU and GPU-based HPC platforms.

MPTRAC is developed openly on GitHub and provides extensive documentation, examples, regression tests, and scientific reference cases. A browser-based Web Runner additionally provides easy access to selected MPTRAC simulations without requiring a local installation.

Features

• Lagrangian atmospheric transport: MPTRAC calculates forward and backward air parcel trajectories by solving the kinematic equation of motion using horizontal wind and vertical velocity fields from global reanalysis and forecast data.
• Transport and mixing: Mesoscale diffusion and subgrid-scale wind fluctuations are represented using stochastic perturbations based on the Langevin equation. An inter-parcel exchange module is available to represent mixing between neighboring air parcels.
• Physical and chemical processes: Optional modules simulate convection, sedimentation, exponential or radioactive decay, gas phase and aqueous phase chemistry, as well as wet and dry deposition.
• Meteorological preprocessing: Dedicated preprocessing tools derive additional quantities such as boundary layer height, convective available potential energy, geopotential height, potential vorticity, and tropopause diagnostics.
• Flexible output and analysis: MPTRAC provides particle, trajectory, grid, ensemble, profile, sample, and station output. Interfaces to Gnuplot and ParaView support scientific visualization and analysis.
• High-performance computing: Hybrid MPI, OpenMP, and OpenACC parallelization, together with dedicated code optimizations, enables efficient execution on systems ranging from single workstations to large HPC clusters and GPU-accelerated platforms.
• Web-based access: The MPTRAC Web Runner allows selected simulations to be configured and executed directly from a web browser without local installation.
• Open-source development: MPTRAC is openly developed and distributed under the terms of the GNU General Public License (GPL).

Getting started

MPTRAC is available from the GitHub repository:

https://github.com/slcs-jsc/mptrac

Detailed information for users and developers is provided in the user manual:

https://slcs-jsc.github.io/mptrac/

The Doxygen documentation is available at:

https://slcs-jsc.github.io/mptrac/doxygen/

For a quick introduction and selected use cases, MPTRAC can also be accessed through the MPTRAC Web Runner:

https://mptrac.jsc.fz-juelich.de

Further information

The following publications provide the main references for citing MPTRAC:

• Hoffmann, L., Clemens, J., Griessbach, S., Haghighi Mood, K., Heng, Y., Khosrawi, F., Liu, M., Lu, Y.-S., Meyer, C., Nobre Wittwer, N., Wu, X., and Zou, L.: MPTRAC: A high-performance Lagrangian transport model for atmospheric air parcel dispersion, Journal of Open Source Software, 10(111), 8177, https://doi.org/10.21105/joss.08177, 2025.

• Hoffmann, L., Baumeister, P. F., Cai, Z., Clemens, J., Griessbach, S., Günther, G., Heng, Y., Liu, M., Haghighi Mood, K., Stein, O., Thomas, N., Vogel, B., Wu, X., and Zou, L.: Massive-Parallel Trajectory Calculations version 2.2 (MPTRAC-2.2): Lagrangian transport simulations on graphics processing units (GPUs), Geosci. Model Dev., 15, 2731–2762, https://doi.org/10.5194/gmd-15-2731-2022, 2022.

• Hoffmann, L., Rößler, T., Griessbach, S., Heng, Y., and Stein, O.: Lagrangian transport simulations of volcanic sulfur dioxide emissions: Impact of meteorological data products, J. Geophys. Res. Atmos., 121, 4651–4673, https://doi.org/10.1002/2015JD023749, 2016.

A more comprehensive overview of publications and scientific applications is available in the reference list.

Contributing

Contributions to MPTRAC are welcome. This includes bug reports, feature requests, documentation improvements, new scientific applications, and code contributions.

Please use the GitHub issue tracker for questions, bug reports, and feature requests. Contributions via pull requests are welcome.

Contact

Dr. Lars Hoffmann
Jülich Supercomputing Centre, Forschungszentrum Jülich
e-mail: l.hoffmann@fz-juelich.de