CMAQ-HDDM v5.4.0.3 O3 sensitivities to NOx emission become abnormal

CMAQ-DDM-3D
1

Hi,
I got unreasonable first- and second-order O3 sensitivities to anthropogenic NOx emission (O3_ENO, O3_2EN) in CMAQ5.0.4.3 when the simulation reaches the second day. The simulation started from September 20th and turned on the online BVOC emission calculation by MEGAN. Apart from the second-order O3 sensitivities to BVOC (O3-2EB in SENGRID file), the others seemed to be reasonable on September 20. On September 21, O3_ENO and all second-order sensitivities in the SENGRID file showed abnormal values while O3_EVA(AVOC) and O3_EVB were reasonable. The daily anthropogenic emissions are constant, while only natural emissions are changing. No sharp emission changes happened.
0920

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0921
0921
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Additionally, why does the sensitivity coefficient of O3 to BVOC appear to be negative?

Looking forward to any help.

Regards,
Runyu Wang

2

As I mentioned in the other thread, I will run some test here using MEGAN to see if I can figure out what is going on with your simulation.

Small negative sensitivities are occasionally not necessarily incorrect and depend on the specifics of your chemical regime.

Sergey