AQCHEM maximum iterations exceeded

CMAQ Chemistry and Aerosols
1

Hello!

I am running CMAQv5.2.1 for nest simulation. But it crashed for certain days with the AQCHEM error: maximum iterations exceeded. There is no NaN or Infinity showing up in my log files.

I know this is caused by MCIP generated METCRO2D file. Because when I run that day with a fake METCRO2D file (copied from other days), it ran well. However, I checked the RC and RN values in the METCRO2D file. There is no negative or unreasonable large value. I don’t know what else in the METCRO2D could cause this error.

Any help is appreciate on how to solve this issue.

Thank you so much
Jay

2

Jay - have you been able to resolve this issue?
@tlspero do you have an idea of how to diagnose this problem?

3

It was caused by my mistake on GRIDDESC file. I set the cell thickness wrong. After I changed it to 1, it runs fine. Your error may be caused by other reasons. But I found my mistakes by turning on debug option while running CMAQ.

Good luck to you.
Jay

1 Like
4

would you tell me how to turn no debug option while running CMAQ ? thanks

5

In the bldit_cctm.csh script, uncomment the line ‘#set Debug_CCTM’

Alternatively, if you already have an existing BLD directory and want to recompile in debug mode, do the following (from Chapter 5 of the User Guide):

cd BLD_CCTM_v53_[compiler][version]
make clean
make DEBUG=TRUE
1 Like
6

Which parameter in the MCIP script is the cell thickness you set? I didn’t find this parameter. In addition, I don’t seem to have the CMAQ debugging option you mentioned