Plume rise model

[Brigitte Rooney]

Hi all,

I am trying to understand more about the plumerise model, specifically how the smoldering phase vs flaming phase is determined. FINN fire_emis generates the wrffirechemi_* files which are input to the plume rise model. They include the fire size, fraction of land by vegetation type, and total wildfire emission flux (smoldering + flaming phase). 

From what I understand, to include FINN in WRF-Chem, you must set the WRF namelist option scale_fire_emis = .true.. The plume rise model then calculates a ratio of smoldering to total emissions based on CO, after allocating them vertically.

Can anyone help me with the module_plumerise1 code? The ratio is applied at each level, surface to plume top. It seems like this would double count some emissions. Is the vertical grid in module_plumerise1 the same as that in module_chem_plumerise_scalar?

-Brigitte

[Gabriele Pfister]

Brigitte,

the factor is needed because the plume rise code only expects the smoldering part of emissions whereas FINN provides the total emission strength. You can easily check that everything is done correctly by comparing the totals in the wrffirechemi* files to the ebu_{species} output from the model. 

Gabriele

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Gabriele Pfister, Acting Director

Atmospheric Chemistry Observations & Modeling

National Center for Atmospheric Research

Email: pfi...@ucar.edu

Phone: +1 303 497 2915

Web: https://staff.ucar.edu/users/pfister

[Brigitte Rooney]

Thanks for the reply, Gabriele.

Do you mean comparing the totals in wrffirechemi to the ebu output from the WRF-Chem run?

Regarding the smoldering to total ratio, I understand why it's used, but I'm a bit confused on how it's used. My understanding is that the surface layer only should be smoldering, so it makes sense to apply this ratio for layer 1. However, above that in the plume, shouldn't the emissions be from flaming? In which cause, it seems like 1-smoldering/total should be applied.

-Brigitte