Hi,
I have to move back to CMAQv5.2 in order to compare ability of PM-10 modeling between CMAQ v5.2 and CMAQ v5.3 because I had extremely lower PM-10 modeling results using CMAQ 5.3 and 5.3.1. [Extremely low PM10 by CMAQv5.3]
However, I got the same issue of CCTM stops running without any error message as you described here when I ran CMAQ v5.2. Because CMAQ 5.2 builder does not have DEBUG option as CMAQ 5.3 does, I checked where and why the CCTM halts (seems suspending) by marking the code (related subroutines and modules) step by step according to log files. I finally found that CCTM is running instead of halting but never reaching to the convergence criteria, and then CCTM actually gets into a infinite loop at Line 281, module SEDIMENTATION.F dealing with sedimentation of aerosols:
281 do while ( adts .lt. dtsec )
I changed this line into the following after I referred to the same module in CMAQ 5.3,
281 do while ( adts .lt. dtsec .and. iter .le. 20). ! you can test different criteria (10, 20, …)
282 iter = iter + 1. ! (do not forget to declare this integer variable, iter)
One of my cases (with different emissions) was crashed with the updates due to AQCHEM total iterations exceeded 60000 (at Line 926 in aqchem.F). The CCTM ran successfully after I increased ICNTAQ to 100000.
I hope this post helps you to figure out why CCTM 5.2 halts at this point. But I highly recommend you to use the latest version of CMAQ.
Thanks.