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Massive-Parallel Trajectory Calculations

Web Runner for Air Parcel Trajectory Calculations

Run MPTRAC in your browser: Set up, run, and visualize air parcel trajectory simulations for atmospheric transport studies. Choose the key input parameters, start the simulation, and download the results for further analysis. This service is under active development. Feedback and bug reports are welcome.

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Simulation Parameters

For a first run, choose a meteorological dataset, set the release time and location, and keep most other default settings unchanged. You can also load a predefined case from the Examples section.

Select a predefined case to fill the form with a complete simulation setup. Choosing an example may overwrite your current entries.

Natural Events
Anthropogenic Events

Select the meteorological dataset that will drive the trajectory simulation. Forecast products mainly support recent dates, while reanalysis datasets cover longer historical periods.

Forecasts
Reanalyses

Define the release time and initial air parcel location. Enter start and stop times in YYYY-MM-DD HH:MM (UTC). Runs can go forward or backward in time, but the total duration must not exceed 30 days.

Set the mean release location of the air parcels. Heights are given in kilometers above sea level and converted internally to pressure. The mean values define the center of the release.

Use uniform or Gaussian spreads to perturb the initial parcel positions in longitude, latitude, and height. Uniform spread defines a bounded release box, while Gaussian spread defines a normally distributed spread around the mean location.

Choose how many air parcels to release. The maximum is 10,000.

Adjust turbulence and subgrid-scale wind parameters for the PBL, troposphere, and stratosphere. For many standard trajectory runs, the default values are sufficient.

Set optional convection thresholds and choose whether to enable vertical mixing throughout the planetary boundary layer (PBL). These settings are mainly relevant for advanced sensitivity studies, and the default values are suitable for standard runs.


Choose how often model output is written during the simulation. Shorter intervals produce more detailed trajectory output, but increase file size and processing time.


Select up to 15 output quantities for the trajectory files. The recommended fields are preselected for standard transport analysis, and fewer variables reduce output size.

Core State
Winds and Dynamics
Humidity and Thermodynamics
Surface and Boundary Layer
Tropopause
Clouds and Convection

Choose whether trajectory output files should be written to the ZIP archive as ASCII or converted to netCDF after plotting. ASCII is simple and transparent, while netCDF is more convenient for structured post-processing.


Choose the settings for the quick-look trajectory plots. These options affect only the plots shown in the browser and do not change the trajectory calculation itself.