Unexpected MOZART-MOSAIC (202) Concentrations After Scaling FINN

[Nafissatou BA]

Hi everyone,

I am running two WRF-LES-CHEM simulations: one baseline (unscaled) and one where I have scaled specific FINN emissions (toluene, benzene, NO, isoprene, HCHO, CO, and C3H6) to better match observations.

Despite increasing both toluene and benzene during the emissions gridding process, my simulation results show unexpected behavior:

• Toluene: The output concentration actually decreased compared to the unscaled run. Consequently, RMSE and MAE increased (worse bias) compared to the baseline.

• Benzene: The output concentrations remained nearly identical to the baseline, with only minimal variations at a few time steps. The RMSE and MAE are completely unchanged, which does not reflect the emissions increase.

Has anyone encountered an issue where scaling up emissions inputs results in a drop or zero change in concentrations? Could this be an issue with the chemistry solver, or perhaps a mapping/index issue during the gridding phase?

Any insights or troubleshooting steps would be greatly appreciated.

Thanks in advance!

Nafissatou