NO fire emissions (FireComp_NO) from CLM5

[Hemraj]

Hi,

I have recently conducted simulations using CLM5 in CESM2.2.0, and I am particularly concerned about the emissions from land fires. I compared several species using both the GFED4 and CMIP6 biomass-burning emissions files. While the emissions of all other species appear to match reasonably well, I noticed that the global NO emissions from CLM5 (3.43 Tg/yr) are approximately four times lower compared to GFED4 (13.6 Tg/yr; average from 2006 to 2015). Could someone please explain why there is such a significant difference?

Thank you.

-Hemraj

 

[oleson]

I don't have an answer to your specific question. Fire emissions appear to be described in the technical note here:

2.24. Fire — ctsm CTSM master documentation

You could contact the people mentioned there, Maria val Martin (m.valmartin at sheffield.ac.uk) and/or Fang Li.

 

[Hemraj]

Thank you @oleson for the information.

 

[m_valmartin@sheffield_ac_uk]

Hi Hemraj, I replied your email but I'm copying the answer here too in case somebody runs into the same question.

The CLM5 fire module has two type of emission factors for nitrogen oxides, NO as NO and NOx as NO. The EFs for NOx are about 2-3 time larger than NO EFs, specially for savannas.

GFED reports fire NOx emissions (as NO). CMIP6 does too as they are based on GFED. So, GFED is using the EFs for NOx, instead of EFs for NO as the CLM5 fire module.

To compare fire NOx emissions from CLM5 to GFED, you need to use FireComp_NOx. Now, I believe it is not output by default so you need to define the variable in your fire_emis_specifier= 'NOx=NOx'.

Another option would be to compare the CLM5 fire species against another fire emission inventory that reports fire NO emissions, for example FINN2.5 (NCAR RDA Dataset ds312.9)

I hope this helps!

Maria

 

[oleson]

Thank you Maria!