Dear CMAQ forum,
I am using saprc07tc_ae6_aq in CMAQv5.2. In my recent simulation for the summer season, surface ozone concentrations were calculated very low. In that simulation, I used emissions data that had shown reasonable results in the past.
I checked PHOTODIAG2 and found that NO2_06 was almost zero, as shown in the attached. So, I thought that NO2 photolysis was not calculated. Does anyone know about the reason for this NO2_06 to be zero?
Appreciate your kind help.
I cannot identify what is causing the problem. Perhaps, examining other variables in the PHOTDIAG1 file may give clues on the cause (such as COSZENS, ETOT_SRC_W381, OZONE_COLUMN, TRANS_DIRECT, TAU_TOT_W381, TAU_CLOUD_w381, TRANS_DIFFUSE, and AOD_W381).
The below plots show possible ranges of their values over the northern hemisphere.
Please post the contents of the CCTM_v52.cfg file.
When you previously obtained reasonable results with this emissions dataset, what version of the model were you using?
Do the values of NO2_O6 increase significantly later in the day, or aloft?
Dear Chris,
Thank you for your comment. I am attaching the cfg file. I cannot see any diurnal variation in NO2_06, but the top level has some value. I used the same V5.2 for the previous calculation.
Thank you for your cooperation on it.
CCTM_v52.cfg.txt (3.1 KB)
Thank you very much for your very useful advice. I will check it out as soon as possible. I will report back as soon as I find out something.
Thank you for your cooperation on it.
I have run CMAQv5.4 with the saprc07tc_ae6_aq chemical mechanism. That has generated larger values of NO2_06.
CMAQv5.2 was released in June 2017, over 6 years ago. It is difficult to reconstruct a platform on which to test such an old version of the code. Is there a compelling reason why you need to run using version 5.2?
Thank you for your comment on it. I understand that upgrading the version may be one of the quickest solution.
I wanted to perform the long term calculation under the same conditions as much as possible without changing the calculation environment.
I will consider upgrading the CMAQ in the future.
