MEGAN3.2 lai or laiv input data

MEGAN
1

Hi everyone,

I’m currently trying to run MEGAN 3.2.

I’ve noticed on the official website it mentions that “MEGAN 3.2 will accept either LAI or LAIv”. So, for Leaf Area Index data, can I convert MCD15A2H data to nc format and directly provide it to megan32_prep_code without calculating LAI/VCF?

I followed the approach mentioned above and ran megan3.2 using LAI data (not LAIv). I obtained lai3.ncf (as shown in the image). Could you confirm if the magnitude of the results (1-10) is correct?

微信截图_20240217165732
微信截图_202402171657321293×887 112 KB

Thank you!

2

Hi @liuhao,

The MEGAN preprocessing code txt2ioapi.f will convert LAI to LAIv if the environmental variable LAIv_YN is set to N when running it:

  setenv LAIv_YN N

I can’t tell if those values are correct by eye. They’re the correct order of magnitude but probably need to be converted to LAIv.

3

I guess the most appropriate way to check this is to move forward directly and then get the MEGAN output to confirm the magnitude of ISOP and TERP emissions.

4

Thank you so much for your help.

5

Hello,

I have a question regarding the LAIv unit in version 3.2. In Version 2.1 user guide it says Laiv unit should be 10 m2. so after we calculate LAI/VCF we have to multiply it by 10. However, I see in version 3.2 source code it uses LAI/VCF without multipling it by 10. So it is a bit confusing to me.