Hi All, So, my CMAQ-DDM over East Asia worked fine until the point where some too big numbers popped out. The SNO2/NOx from SENSGRID over three days: [DDM1] [DDM2] [DDM3] Is it a numerical diffusion? I tried to reduce the time step but it didn’t help. I remembered the same issue happened sever…

It was caused by a rapid change in my emissions. No issue with the DDM.

Hey Amir, I’ve been encountering a similar issue with my CMAQv5.2 DDM simulations, can you elaborate a bit more on what the issue was for your case? Thanks, Calvin Arter

Hi Calvin, Check the emissions first. If my memory serves, when I merged bio emissions into anthro ones, I missed one hour so it resulted in a sharp change emission from one hour to another. Amir

Hi, how much has the emission changed? I am currently facing the same problem with CMAQ version 5.4.0.3.

CMAQ-DDM produces NaN values at certain point

CMAQ-DDM-3D

lizadams March 30, 2025, 7:45pm 6

Please start a new topic and review the tips found in Please read before posting. Closing this issue.

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CMAQ-DDM produces NaN values at certain point

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