CMAQ5.3.1 IPR DDEP is positive?

CMAQ
1

Hi everyone,
When I used the IPR module of CMAQ5.3.1 to analyze the formation of HONO, I encountered a very confusing problem. That is, DDEP is positive and becomes an important source of HONO, which is unreasonable. But I am not really sure why this happens.
I would appreciate any guidance or feedback on this issue.

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ORI: CMAQ default
REV: ORI + vehicle emissions + heterogeneous reactions

2

Dear Xuan,

Heterogeneous HONO production in CMAQ occurs on aerosol and ground surfaces. Heterogeneous HONO production on aerosol is implemented in AEROSOL_CHEMISTRY.F and heterogeneous HONO production on ground is implemented in dry deposition module.

Thanks,
Sarwar

1 Like
3

I understand now, thank you very much for your guidance! If I only want to observe the dry deposition of HONO from a physical perspective, should I modify m3dry.F? It seems that the file only contains the generation amount of HONO through the conversion from NO2.

pvd( n,c,r ) = kno2 * conc_no2 * MET_DATA%ZF( c,r,1 )

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You can turn-off the heterogeneous HONO production on ground by assigning kno2 = 0.0 in m3dry.F or by revising the run script. You can set N to the following line in the run script to turn-off the heterogeneous HONO production on ground.
setenv CTM_SFC_HONO N #> surface HONO interaction [ default: Y ]

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5

I appreciate your help and will address this issue as you suggested.