Using updated biogenic emissions namelist option (bio_emiss_opt = 4, MEGAN v2.1)

[dehuber]

Hi there,

I see that biogenic emissions from MEGAN v2.1 became an option starting with WRF v4.3 by setting bio_emiss_opt=4 in the WRF namelist file, which also requires the use of the CLM land surface model option (sf_surface_physics=5). Looking at the description of this newer biogenic emissions option in the WRF github repository (Develop new CLM / MEGANv2.1 interface by davegill · Pull Request #1425 · wrf-model/WRF), the developers said one of the key changes was that:

"the code is looking for a variable of name 'PCT_PFT' in the wrfinput file; it is up to the user to use external software to insert the variable containing the percentages for each CLM PFT".

Where can the plant functional type (PFT) percentages for CLM4 be found, and how many different PFT layers need to be included in the 'PCT_PFT' variable?

With bio_emiss_opt=3, which uses MEGAN v2.04, the biogenic emissions preprocessor provides 4 PFT percentages in the wrfbiochemi file: broadleaf trees, needleleaf trees, shrub and bush, and herbs. But after digging into the CLM4 documentation, it appears that there are up to 16 different PFTs associated with CLM4 (https://www.cesm.ucar.edu/models/cesm1.2/clm/CLM4_Tech_Note.pdf). So I assume the PFTs provided in the wrfbiochemi file for bio_emiss_opt = 3 cannot be used as the PFTs needed for bio_emiss_opt=4.

Any help with this would be appreciated!

 

[jordanschnell]

Hi Dehuber,

You are correct that you need alternative PFTs than those used in MEGAN v2.04. You can find the data you are looking for here: https://bai.ess.uci.edu/megan/data-and-code/megan2, though it will be up to you to regrid to your domain and insert the fields. You may also want to reach out to Brian Gaudet: PNNL: Contacts: Staff Information

Jordan

 

[An-bao Zhu]

Hi Dehuber,

You are correct that you need alternative PFTs than those used in MEGAN v2.04. You can find the data you are looking for here: https://bai.ess.uci.edu/megan/data-and-code/megan2, though it will be up to you to regrid to your domain and insert the fields. You may also want to reach out to Brian Gaudet: PNNL: Contacts: Staff Information

Jordan

Hi Jordanschnell,

I also want to use MEGAN2.1 in the WRF-CHEM4.5 model and we found that we should manage input of MEGAN emissions factors from netCDF file when we are running MEGAN2.1 in the WRF-CHEM model. However, we cannot find any information about the MEGAN emissions factors from netCDF file. Thus, we want to know that how can we make the MEGAN emissions factors file from netCDF file and how does the WRF-CHEM model read the file (i.e., does it mean we should read the MEGAN emissions factors through setting the namelist.input file that likes as the wrfbiochemi_do1 file?). Can you give me some useful information or some websites providing test cases? Thanks very much for your help and I'm looking forward to your reply.

Best regards,
Anbao Zhu

 

[dawnfruit]

Hi Jordanschnell,

I also want to use MEGAN2.1 in the WRF-CHEM4.5 model and we found that we should manage input of MEGAN emissions factors from netCDF file when we are running MEGAN2.1 in the WRF-CHEM model. However, we cannot find any information about the MEGAN emissions factors from netCDF file. Thus, we want to know that how can we make the MEGAN emissions factors file from netCDF file and how does the WRF-CHEM model read the file (i.e., does it mean we should read the MEGAN emissions factors through setting the namelist.input file that likes as the wrfbiochemi_do1 file?). Can you give me some useful information or some websites providing test cases? Thanks very much for your help and I'm looking forward to your reply.

Best regards,
Anbao Zhu

Dear Jordan,

I also have a same problem like Dr. Zhu above, in the WRF-CHEM v4.5 during running the CLM-MEGAN coupling (bio_emiss_opt = 4).
When I check the rsl.out.0000, it is written like below;
-------------------------------------------
megan_factors_file

clminit: B4 call to megan_factors_init
megan_factors_init: failed to open file
NetCDF: Malformed URL
-------------------------------------------
netcdf.inc cannot find the appropriate nc file (named filename at module_sf_clm.f90) which has not been introduced in manual or the release note.
./module_sf_clm.f90:4103: subroutine megan_factors_init( filename )
./module_sf_clm.f90:4142: err_msg = 'megan_factors_init: failed to open file ' // trim(filename)

Would you please suggest how to deal with this matter?

With regards,
Daniel Choi