ERROR in COMBINE for CMAQ5.3.2-ISAM

[Rain]

Thank you for your attention. Following your advice, I checked the relevant variables, and as you mentioned, the *_XAF PM concentration is indeed zero. Based on other posts on the forum, I found the cause of the problem and am now working on resolving it. Thanks again for your help.

CCTM output is all 0 after running CMAQ

Hello, Yes, the variable in your region mask file should be in real format. You may straightforward use ncflint to convert them from integer to float or refer to Cristian’s suggestion, and see if your CMAQ/ISAM works. Try to use m3fake instead of t3mask in t3tool, please refer to https://forum.cmascenter.org/t/error-creating-gridmask BTW, I created my mask files using ArcGIS and ncgen. Thanks.

How to make ISAM_REGIONS file?

As far as computers are concerned, we don’t have “fractions” – only “bit patterns” that are interpreted according to variable-type. And fortunately the REAL and INTEGER bit-patterns are the same (all bit-zeros)…