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Update MEGAN

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New member
I am interested in updating the biogenic emissions model in WRF-Chem, MEGAN.
I would like to know if there are other groups that have updated input data (LAI, etc. ) or the model code (module_data_megan2.F). I would like to include a new PFT and update the EF in file module_data_megan2.F.


Hi Alba,

MEGAN 2.1 coupled to CLM was recently released as part of the community WRF-Chem version:

Beyond that, I am not aware of any groups that have recently made changes. I do know that A. Guenther et al have released MEGAN 3.0 in the last year or two, which we would love to have coupled...

Either way, I'm happy to work with you on making additions/improvements to the community code.

Hello Jordan,

Thank you for your message.

I am going to try the MEGAN2.1 coupled to CLM. Is there any User guide to know which input files I need to run MEGAN2.1 coupled to CLM? The latest user guide is the "WRF-Chem Version User's Guide".

However, I am using the urban canopy model BEP/BEM ( sf_urban_physics = 3). Let's see if I can use this version of MEGAN/CLM with the urban canopy model.


Hi Alba,

There is not yet an updated UG for post-3.9.1, but it is coming... You can check out the PR for the MEGAN code which may help you:

Thank you, Jordan!

Do you know if this version is coupled with the urban canopy model BEP/BEM ( sf_urban_physics = 3)?

I had a chat with Brian Gaudet at the beginning of 2020 and he told me" The CLM code does have some existing structures involving urban usage, and some coupling to option sf_urban_physics=1 (Noah urban canopy model) – so this could probably be adapted to other schemes, but would take some development I think.".


Dear all,

I have downloaded both LAI and FCOVER data required to calculate LAIv for Megan model. I will be glad if I could get any script I can use to process the files so as to get LAIv files for megan?

Note that these LAI data must first be converted to LAIv (LAI divided by the vegetation cover fraction) before used in MEGAN. For example, if the LAI for a specific location is 2 m2/m2 and the vegetation cover fraction (VCF) is 0.4 then the LAIv = LAI/VCF = 2/0.4 = 5. Note that the unit used for input to MEGAN2.1 and MEGAN3 pre-processor is m2 leaf area per 10 m2 surface area so if you generate LAIv in m2/m2 then multiply this by 10 to get m2 leaf area per 10 m2.

Thanks an kind regards