HYSPLIT Forum: hysplitbbs.arl.noaa.gov

Hello,

I'm running a dispersion simulation using the attached files (CONTROL, SETUP, EMITTIMES). Upon examining PARDUMP.txt, I've observed that while I can accurately compute the mass of puffs in the air at various time instant when considering puffs located at a height > 0, there appears to be a significant portion of puffs deposited on the ground missing. As a result, I'm unable to calculate the cumulative deposited mass from PARDUMP.txt.

Is there a method to ensure that all puffs, both those on the ground and those in the air, are included in PARDUMP.txt? This would allow for the accurate computation of the total mass released during the simulation, encompassing both deposited and airborne particles.

I've noticed that some latitude and longitude values are equal to 0. Could these correspond to the missing deposited puffs?

Many thanks
Best
Federica

The PARDUMP file does not contain information about mass that has been deposited. To see how much mass has been deposited and where refer to the cdump file. You have your concentration grid set with two levels 0, 30000. That first level, 0, will be the deposition layer.
https://www.ready.noaa.gov/hysplitusersguide/S313.htm

1
37.73 15.0
0.05 0.05
5.0 5.0
./
cdump_part_Etna_test
2
0 30000
18 12 24 12 00
00 00 00 00 00
1 0 10

Note that there are no 'puffs' or 'particles' 'on the ground'. See below for how deposition is usually calculated.

https://www.ready.noaa.gov/hysplitusersguide/S314.htm
Note that the normal deposition mode is for particles to lose mass to deposition when those particles are within the deposition layer. Thus deposition will not decrease the number of computational particles in the model, but only decrease the amount of mass carried on the particles. An option to deposit the entire particle's mass at the surface (the particle is removed) when subjected to deposition is available. See Deposition and Decay for further information.
https://www.ready.noaa.gov/hysplitusersguide/S441.htm
The normal deposition mode is for particles to loose mass to deposition when those particles are within the deposition layer. An additional option was added to deposit the entire particle's mass at the surface (the particle is removed) when subjected to deposition. To insure the same mass removal rates between the two methods, a probability of deposition is computed, so that only a fraction of the particles within the deposition layer are deposited in any one time step. The probability of deposition is a function of the deposition velocity, time step, and depth of the layer. One limitation of this method is that only one mass species may be assigned to a particle. The probability deposition method can be invoked from the namelist file with ICHEM=5.