CMAQ-DDM for v5.3.3

I noticed previously in the bldit script for CMAQv5.3.1, that there was no option to compile DDM. With the recent versions of CMAQ now (i.e 5.3.3), I see it is listed as an option. Although the MECHs directory does not appear to be updated. Is DDM available with 5.3.3?


Hi Abi, Thank you for your interest in CMAQ-DDM. DDM was not released as an option with the v5.3.X series but has been under development and will be included with CMAQv5.4 which is scheduled for release later this year.

Thanks Kristen!
Looking forward to using it!!!
Will it be with ae7? Just curious!!

For current DDM use, we should continue to use CMAQ5.2-DDM and ignore the bldit options for DDM under CMAQv5.3.3, correct?


Hi Abi,
In CMAQv5.4 DDM will be fully integrated with the base model as a compile time option. The base mechanism for CMAQv5.4 will be cb6r5_ae7.

In addition, the v5.4 DDM updates include automatic inline Jacobian generation to improve compatibility with more gas chemistry mechanisms.

I defer to @sergey on your question of whether or not to use the DDM files in the v5.3.3 release.

1 Like

Thanks Kristen @foley.kristen and @sergey! Really looking forward to using v5.4 DDM!!!