Hello,
I am using inputs for in-line MEGANv3.2 from the 2018 EPA modeling platform, including a FERT_CONUS file to be used with BDSNP. From a previous communication with @willison.jeff , this was generated by the model developers from Potter fertilizer data using the MEGAN preprocessor. However, it’s unclear to me what the units mean here, as the file metadata lists them as “ng/m3”. Is this ng N? Additionally, is it really m3, or m2? If it’s the former, what is the non-area component for volume? We are comparing these results with fertilizer use in FEST-C and are struggling to compare their magnitudes.
This is a good question that I was unable to answer myself. I reached out the creators of this input file a couple years ago but never heard back.
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I received a response from Ling Huang, who implemented the NO emissions module in MEGANv3.2:
“The fertilizer file (or more precisely, the available nitrogen due to fertilizer application) has a unit of ng/m3 of N. It is actually ng/m2. We kept “ng/m3” as the previous global one from GEOS-Chem also uses “ng/m3” although it is actually “ng/m2” (I forgot where I saw the explanation for this, but I definitely saw this).”
Looks like it is indeed ngN/m2.
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