- My BCON inputs were prepared using global model outputs whose data is 6-hourly; thus the BCON file has data at 0:00, 6:00, 12:00, and so on.
- My daily CMAQ run starts at 8:00 (regional modeling for California is often done this way so that daily inputs/outputs cover mindnight to midnight in local time).
- CMAQ (v5.3.3) stops with error saying it can’t read BCON data at the model start time.
It looks like the problem is in the subroutine centralized_io_init where it assumes BCON data at the model start date/time is available (which is not always true as in my case):
call retrieve_boundary_data (cio_model_sdate, cio_model_stime)
Fixing this is a bit tricky: I don’t think you can simply replace cio_model_stime in the above call with file_stime(f_bcon) because the subroutine may also read METBDY3D file which has its own start time (typically matching the model start time).
My quick-and-dirty solution was setting loc_jtime inside the subroutine retrieve_boundary_data to jtime if the optional argument vname is present (non-intialization call); to file_stime(f_bcon) if vname is not present (initialization call).
A more elegant solution should come.