Issue about new windblown dust emission parameterization in CMAQ

CMAQ
1

Dear all,
I hope this email finds you well. This is Ryan, a Ph.D. student from the University of California, Irvine. Recently I am working on implementing the new windblown dust emission parameterization developed by you in CMAQ. However, I have an issue which I would like to ask you.
Q1: As described on the website,
#### 4. Use the MODIS FPAR and LAI data in the CCTM
The output file (MODIS_FPAR_LAI_daily.nc.ioapi) is ready to be used by CMAQ. Include the path to this file in the runscript:
setenv MODIS_FPAR /path/to/MODIS_FPAR_LAI_daily.nc.ioapi
After following all the steps of your guidance, I have successfully generated the MODIS_FPAR_LAI_daily.nc.ioapi file. However, I am confused about whether I only need to set the setenv MODIS_FPAR /path/to/MODIS_FPAR_LAI_daily.nc.ioapi in my run.cctm.csh script and set the setenv CTM_WB_DUST N ?
Otherwise, I should still set the setenv CTM_WB_DUST Y and generate the BELD files used for inline windblown dust emission by using the Spatial Allocator?

Best regards,
Ryan

2

@hoseinforoutan Please have a look at this issue when you have a free moment, thanks!

3

Hi Ryan,

To clarify what each environment variable does:

setenv CTM_WB_DUST Y : Turns ON the dust module. You always want this to be Y if you are doing a dust simulation.

setenv MODIS_FPAR /path/to/MODIS_FPAR_LAI_daily.nc.ioapi : Tells the dust module about the path to your vegetation file. This is no longer needed in v 5.3 and v 5.3.1 as vegetation data is being read from met input files.

BELD files contain information about erodible lands (static data and different from vegetation) needed by the dust module.

Hope this helps.

4

Hi Professor Foroutan,
Thanks for getting back to me so quickly. I have an additional question as described below:
If I want to use the dust module in CMAQv5.3.2 (v5.3.1, v5.3), then I don’t need to generate the MODIS_FPAR_LAI_daily.nc.ioapi file whereas the DUST_LU_1 and DUST_LU_2 (as shown below in the run.cctm.csh) are still needed, right?
setenv DUST_LU_1 $LUpath/beld3_12US1_459X299_output_a_bench.nc
setenv DUST_LU_2 $LUpath/beld4_12US1_459X299_output_tot_bench.nc
If it is the case, these two files can be generated by using the Spatial Allocator if I am studying the US domain (as far as I know). However, I am focusing on East Asia. Thus, could you please tell me how to generate these files for East Asia?
Any comments and guidance are highly appreciated!
Wish you a happy weekend!

Ryan

@hoseinforoutan

5

Ryan,
Yes - That’s right.
Now, regarding DUST_LU_1 and DUST_LU_2: Both of them are optional files in case you want to provide additional information about your land use type to the dust module. If you don’t provide these two files, the code should use input from MCIP/WRF. Please see this: https://github.com/USEPA/CMAQ/blob/master/DOCS/Users_Guide/CMAQ_UG_ch06_model_configuration_options.md#wind-blown-dust
as well as many other posts in this forum.

6

Hi Professor Foroutan,
Please allow one more question. If I am considering not providing the DUST_LU_1 and DUST_LU_2 files, should I comment out these lines like
#setenv DUST_LU_1 $LUpath/beld3_12US1_459X299_output_a_bench.nc
#setenv DUST_LU_2 $LUpath/beld4_12US1_459X299_output_tot_bench.nc
and setenv CTM_WB_DUST Y for running dust module with inputs from MCIP files?
Am I correct?
Thanks again for your help!

Ryan