Changing particle density and size during Concentration calculation

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sphilippe
Posts: 1
Joined: August 21st, 2020, 9:09 am
Registered HYSPLIT User: Yes

Changing particle density and size during Concentration calculation

Post by sphilippe »

Dear Hysplit team,

I am working on a problem where particle size and density change with time. While I do not seek to create a new complex chemistry module, I am exploring the possibility to simply readjust the particle size and density at a given time step (switch from distribution 1 to distribution 2 while keeping track of the location of the 3D particle). Is that something possible? And where could I start?

I was thinking that it could perhaps be a modification of the ICHEM=2 option, but for more particle type?
Or simply start a new run from a PARDUMP file, with the possibility to change particle size and density in the next run?

Thank you for any ideas you may have.

Sebastien
alicec
Posts: 251
Joined: February 8th, 2016, 12:56 pm
Registered HYSPLIT User: Yes

Re: Changing particle density and size during Concentration calculation

Post by alicec »

It sounds like you should be able to use the ichem=2 and the CHEMRATE.TXT file.
https://www.ready.noaa.gov/documents/Tu ... inear.html

You could define multiple pollutatants and then specify the conversion rates.
something like

1 2 1.0 1.0
2 3 1.0 1.0
3 4 1.0 1.0
start off with emitting only particle 1 and then would have conversion to particle 2 which would
then eventually convert to particle 3 which would then convert to particle 4.

If you are a python user, the following has a PARDUMP file reader which may be useful
for figuring out if HYSPLIT is doing what you think it is doing. It returns a Pandas DataFrame.
https://github.com/noaa-oar-arl/monetio
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