How to get AOD in CMAQ5.3.1

CMAQ
1

Hi,
Could anybody suggest how to output AOD in CMAQ output? If it is not directly output, any formula to compute this would be appreciated. AOD at wavelengths near blue, and red would be most desirable.

And also, for visibility (please).

Thanks

2

You can obtain column AOD as well as layer-specific aerosol extinction, extinction due to Rayleigh scattering, and total extinction by turning on the CTM_PHOTDIAG variable in your run script.

Column AOD will be written to CCTM_PHOTDIAG1 while layer-specific aerosol extinction, extinction due to Rayleigh scattering by NO2 and O3, and total extinction will be written to PHOTDIAG3. The total extinction in layer 1 is a measure of visibility.

Please see the CMAQv5.3 Release Notes for further documentation on photolysis diagnostics, including an overview of the wavelengths for which these diagnostics are calculated.

2 Likes
3

Thank you, I will try that

4

That worked. thank you @hogrefe.christian . By the way is there setting for outputting wet and dry deposition velocities for all layers? Ideas is to get combined ACONC for all layers

5

No, the wet and dry deposition values in CCTM_DRYDEP and CCTM_WETDEP1 represent 2-D fluxes at the surface.

However, the fact that the deposition fluxes are 2-D does not prevent you from creating 3-D concentration files with combine. The sample combine script creates two separate output files, one for concentrations and one for deposition fluxes. Two separate species definition files are used to create these two files. While the output file for deposition values will always be 2-D, the concentration file can either be 2-D or 3-D.

If you want to create a 3-D concentration file, you will have to edit the file referenced by the SPEC_CONC variable in the run script to add an exclamation mark before the statement “#layer 1” on the third line. You will also have to comment out all definitions that reference the file METCRO2D (i.e. most of the meteorological variables and the FRM PM calculations at the end of the file) since this file only has 1 layer. Finally, you will have to comment out the setting of INFILE4 to METCRO2D in the combine run script and you have to make sure that you modify your CMAQ run script such that ACONC and APMDIAG have the same number of layers as the METCRO3D file.

2 Likes
6

Thank you for the detailed reply. I will try with that.