# Issue about new windblown dust emission parameterization in CMAQ **URL:** \ **Category:** CMAQ\ **Created:** [November 5, 2020, 10:51pm UTC](https://forum.cmascenter.org/t/issue-about-new-windblown-dust-emission-parameterization-in-cmaq/1893 "2020-11-05T22:51:53Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Ryan](https://avatars.discourse-cdn.com/v4/letter/r/a8b319/32.png) [@Ryan](https://forum.cmascenter.org/u/Ryan)\ **Post date:** [November 5, 2020, 10:51pm UTC](https://forum.cmascenter.org/t/issue-about-new-windblown-dust-emission-parameterization-in-cmaq/1893/1 "2020-11-05T22:51:53Z")
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 ---
**Author:** ![Ryan](https://avatars.discourse-cdn.com/v4/letter/r/a8b319/32.png) [@Ryan](https://forum.cmascenter.org/u/Ryan)\ **Post date:** [November 5, 2020, 10:52pm UTC](https://forum.cmascenter.org/t/issue-about-new-windblown-dust-emission-parameterization-in-cmaq/1893/2 "2020-11-05T22:52:33Z")
@hoseinforoutan Please have a look at this issue when you have a free moment, thanks! ---
**Author:** ![hoseinforoutan](https://avatars.discourse-cdn.com/v4/letter/h/e68b1a/32.png) [@hoseinforoutan](https://forum.cmascenter.org/u/hoseinforoutan)\ **Post date:** [November 6, 2020, 3:50am UTC](https://forum.cmascenter.org/t/issue-about-new-windblown-dust-emission-parameterization-in-cmaq/1893/3 "2020-11-06T03:50:30Z")
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. ---
**Author:** ![Ryan](https://avatars.discourse-cdn.com/v4/letter/r/a8b319/32.png) [@Ryan](https://forum.cmascenter.org/u/Ryan)\ **Post date:** [November 6, 2020, 4:30am UTC](https://forum.cmascenter.org/t/issue-about-new-windblown-dust-emission-parameterization-in-cmaq/1893/4 "2020-11-06T04:30:17Z")
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 ---
**Author:** ![hoseinforoutan](https://avatars.discourse-cdn.com/v4/letter/h/e68b1a/32.png) [@hoseinforoutan](https://forum.cmascenter.org/u/hoseinforoutan)\ **Post date:** [November 6, 2020, 5:00am UTC](https://forum.cmascenter.org/t/issue-about-new-windblown-dust-emission-parameterization-in-cmaq/1893/5 "2020-11-06T05:00:11Z")
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](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. ---
**Author:** ![Ryan](https://avatars.discourse-cdn.com/v4/letter/r/a8b319/32.png) [@Ryan](https://forum.cmascenter.org/u/Ryan)\ **Post date:** [November 6, 2020, 5:30am UTC](https://forum.cmascenter.org/t/issue-about-new-windblown-dust-emission-parameterization-in-cmaq/1893/6 "2020-11-06T05:30:52Z")
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 ---
**Author:** ![Catalyst2682](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Catalyst2682](https://forum.cmascenter.org/u/Catalyst2682)\ **Post date:** [October 9, 2025, 12:51pm UTC](https://forum.cmascenter.org/t/issue-about-new-windblown-dust-emission-parameterization-in-cmaq/1893/7 "2025-10-09T12:51:13Z")
@Ryan @hoseinforoutan Please, how can I generate the MODIS\_FPAR\_LAI\_daily.nc file? It’s required in CMAQ-5.2 for dust simulation. @lizadams Thanks