@@ -17,11 +17,11 @@ The initial position of the tracking particles is determined by the injection bo
#### Reference Values
For thermochron age calculation, the scaling values are needed. Specify `lref`, `veloref` and `rhoref` as used for the scaling of DOUAR input parameters.
### Post-Processing
### Internals
The tracking cloud is a derived type that is activated at a user-specified timestep. The particles are injected in a box, either randomly or in a spaced grid and advected through the domain according to osolve velocities. Every n'th timestep, the position, temperature and (smoothed) pressure for these particles is written to a tracking output file (in separate subdirectory). If a particle hits the surface, its track extent is saved in a log array and the particle reinjected. If a particle exits through the side of the domain, the track is discarded and the particle reinjected. Reinjection happens in those elements that have the largest decrease in tracking particle density compared to the initial distribution.
The tracking cloud is implemented as a derived type, similar to the regular cloud. The particles are advected through the domain according to osolve velocities. Instead of saving the entire history within DOUAR, position, temperature and pressure are writtend to disk and reassembled in post-processing. If a particle hits the surface, its track extent (particle ID, timestep of injection and timestep of exhumation) is saved in a log array and the particle reinjected. If a particle exits through the side of the domain, the track is discarded (i.e. not written to the log array) and the particle reinjected. Reinjection happens in those elements that have the largest decrease in tracking particle density compared to the initial distribution.
In post-processing, either the entire path of all particles or only the surfaced tracks saved in the log array can be converted to vtk-files. Multiple output files regularly spaced in step number can be created at once. Input files can be regularly spaced as well. Usually only tracks that surfaced at the output timestep are written to the vtk file, but for an increase in density, surfaced tracks can be 'accumulated' over several timesteps.
Output variables for the tracks are: Speed, vertical speed, temperature, pressure, time, step number and particle/track ID. Variables and positions are written either in DOUAR units or natural units.
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Note on vocabulary: The expression _track_ describes a the history of a surfaced particle. Since the particle is then reinjected, a particle with a given _particle ID_ can have several tracks, each with its own _track ID_.
