Can CMAQ output Jvalue of NO2?

I am wondering if CMAQ could output Jvalue of NO2.
I think it could, but I dont know where to find it. I want to ouput the value for an OBM model.
Can anybody show some guidance?
Thanks a lot

Hi Wangnan,

CMAQ does output the photolysis rates for NO2 and other species undergoing photolysis reactions.

This additional diagnostic information can be output when you run the chemical transport model (CCTM) for a specific domain. To do so, prior to your run, specify the shell environmental variable in your runscript :

setenv CTM_PHOTDIAG Y #> photolysis diagnostic file [ default: N ]

Note: By default, this variable is set to “N” to save disk space

This will tell the “inline” photolysis module to output diagnostic information regarding photolysis rates including “JNO2” to a netCDF file called “CCTM_PHOTDIAG1”. Please note, that this information is only available for LAYER 1 (i.e., the surface).

For 3D photolysis rates an additional variable must be set in your runscript:


Note: Where the “1” represents the number of layers you want, bounded by the model top. For example, if my model has 35 layers, and I wanted all 35 layers, I would request “35”.

This will produce a 3-D diagnostic netCDF file called CTM_PHOTDIAG2, in which you will find the “JNO2” photolysis rate labeled as the name used in the gas phase chemistry mechanism – “NO2_IUPAC10” for CB6, “NO2_RACM2” for CRACMM and RACM2, “NO2_06” for SAPRC.

For additional documentation regarding this file please see:

Hope this helps!