# Some question about MEGAN

**URL:** <https://forum.cmascenter.org/t/some-question-about-megan/3530>\
**Category:** MEGAN\
**Created:** [August 29, 2022, 10:56am UTC](https://forum.cmascenter.org/t/some-question-about-megan/3530 "2022-08-29T10:56:52Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Bartley](https://avatars.discourse-cdn.com/v4/letter/b/eb8c5e/32.png) [@Bartley](https://forum.cmascenter.org/u/Bartley)\
**Post date:** [August 29, 2022, 10:56am UTC](https://forum.cmascenter.org/t/some-question-about-megan/3530/1 "2022-08-29T10:56:52Z")

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I want to understand the relevant mechanism of MEGAN preprocessor processing LAIv data, is it in the f90 file, where is the specific location?  
I would be grateful if you could help me,thank you

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**Author:** ![lizadams](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@lizadams](https://forum.cmascenter.org/u/lizadams)\
**Post date:** [September 6, 2022, 9:44pm UTC](https://forum.cmascenter.org/t/some-question-about-megan/3530/2 "2022-09-06T21:44:25Z")

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Hi,  
Please contact the developer/maintainers at University of California, Irvine.

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**Author:** ![Ryan](https://avatars.discourse-cdn.com/v4/letter/r/a8b319/32.png) [@Ryan](https://forum.cmascenter.org/u/Ryan)\
**Post date:** [September 6, 2022, 10:35pm UTC](https://forum.cmascenter.org/t/some-question-about-megan/3530/3 "2022-09-06T22:35:48Z")

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You could find the prepmegan4cmaq\_lai.f90 file in the tarfile of prepmegan4cmaq\_2014-06-02 in case if you are using MEGANv2.1.

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**Author:** ![rrezaei83](https://avatars.discourse-cdn.com/v4/letter/r/53a042/32.png) [@rrezaei83](https://forum.cmascenter.org/u/rrezaei83)\
**Post date:** [September 8, 2022, 12:35pm UTC](https://forum.cmascenter.org/t/some-question-about-megan/3530/4 "2022-09-08T12:35:25Z")

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@Bartley  
In MEGANv3.2, the _ **prepmegan4cmaq\_lai.f90** _ file is the relevant mechanism of LAIv data under “_/MEGAN32\_Prep\_Code_”.

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**Author:** ![FengLiu](https://avatars.discourse-cdn.com/v4/letter/f/49beb7/32.png) [@FengLiu](https://forum.cmascenter.org/u/FengLiu)\
**Post date:** [September 8, 2022, 10:11pm UTC](https://forum.cmascenter.org/t/some-question-about-megan/3530/5 "2022-09-08T22:11:13Z")

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@Bartley

Yes, as @rrezaei83 mentioned the LAIv processing program is _ **prepmegan4cmaq\_lai.f90** _ in MEGAN32\_Prep\_Code\_Jan\_2022. You may download it from [MEGAN32\_Prep\_Code\_Jan\_2022.tar.gz - Google Drive](https://drive.google.com/file/d/1R0oPCqzj8eNhg3ltfy9LRrGcyA4kbifF/view).

On LAIv data description you can refer to [UCI BAI - LAI](https://sites.google.com/uci.edu/bai/megan/data-and-code/lai)

Note that LAIv data in urban area is not available in the dataset linked above. You have to fill urban LAI yourself otherwise biogenic emissions in urban area will be zero.