trcloud.md

@@ -6,11 +6,17 @@ The tracking cloud is an additional feature of DOUAR that can be used to calcula
 
 #### Activation and Saving
 
-In the input file, set `ptracking = T`. The tracking cloud will be activated at timestep `tr_activation` (larger than nstep_spinup is recommended) 
+In the input file, set `ptracking = T`. The tracking cloud will be activated at timestep `tr_activation` (larger than nstep_spinup is recommended). The current state of the tracking cloud will be written to disk every `tr_savstep`th timestep, including an array specifying _all_ particles and their tracks that have reached the surface up to this timestep.
 
 #### Injection Box
 
-#### Reference 
+The initial position of the tracking particles is determined by the injection box. Specify `trbox[xyz]min` and `trbox[xyz]max` for its extent. The box is filled either
+ * **randomly:** Set `gridtrack = F` and `ntrp` for total number of particles.
+ * **gridded:** Set `gridtrack = F` and `ntrp[xyz]` for the number of particles in each dimension.
+
+#### 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