Unit of Isoprene in WRF-Chem

[Pradeep Attri]

Hello Everyone, 

I have come across few doubts. i will be happy if anyone can help me with these. 

1.   what is the difference between 'isopn' and 'isopr' in the WRF-chem

2. I would like to know what is the unit of Isoprene (isopr) in the WRF-chem model. It is shown with (-).

3. how may I get NM-VOCs? do I have to sum up few species to get the NM-VOCs 

please help me with these questions. Any help will be highly appreciated.

 float isopr(time, lev, lat, lon) ;

                isopr:long_name = "isoprene (-)" ;

                isopr:_FillValue = 1.e+30f ;

                isopr:missing_value = 1.e+30f ;

 float iso2(time, lev, lat, lon) ;

                iso2:long_name = "iso2 (-)" ;

                iso2:_FillValue = 1.e+30f ;

                iso2:missing_value = 1.e+30f ;

      

Best regards

-Pradeep Attri 

[Gabriele Pfister]

Hi Pradeep

I am not sure which chemical mechanism you are using but 

isopr should be the isoprene concentration in ppm and 

isopn is the concentrations of peroxy radicals in ppm resulting from the reaction: 

ISOP+NO3=ISOPNO3             

You can easily look up the species in the KPP mechanisms files in the source code:

./chem/KPP/mechanisms/{mechanism}

The {mechanisms}.eqn includes the list of chemical reactions. The file

{mechanisms}.equiv includes the mapping of those species names which differ 

between the mechanism files and the names in the WRF-Chem code itself. 

Yes, to get total NMVOC you have to add up all the individual NMVOC species. 

Gabi

--

================================
Gabriele Pfister, Interim NCAR Associated Director

Atmospheric Chemistry Observations & Modeling

National Center for Atmospheric Research (NCAR)

Email: pfi...@ucar.edu

Phone: +1 303 497 2915

Web: https://staff.ucar.edu/users/pfister

[Pradeep Attri]

I am using wrf-chem with version 3.9.1.1  so which scheme would be best to use to simulate isoprene. because I checked that chem_opt=114 which is for T1_MOZCART scheme is available in wrfchem_v4. 

 so can you please suggest me. If I am using V3.9.1.1, which scheme is best to simulate isoprene.

Regards

Pradeep

[Gabriele Pfister]

Pradeep, 

Isoprene itself is largely controlled by emissions, but I assume you talk about the chemistry of isoprene and other BVOCs. 

Depends on what you are interested in. If you also look at aerosols, then you definitely have to use MOZART-MOSAIC since GOCART does not have SOA. 

If you are only interested in gas phase chemistry, then you should consider using T1-MOZCART. The gas phase chemistry is significantly updated over MOZCART. 
See https://www2.acom.ucar.edu/wrf-chem for more information.

Note the calculation of the emissions in all these schemes is based on MEGAN. However the MEGAN version in WRF-Chem is not the most recent version

and this is also true for the land cover information. See 

https://gmd.copernicus.org/articles/9/1959/2016/

for information about the MEGAN implementation in WRF-Chem and considerations in this regard.

Gabi

[Alma Hodzic]

Hi Pradeep

If you are interested in aerosols, please keep in mind that IEPOX-SOA is not available in any package with MOZART.

Best

Alma

--

Alma Hodzic Roux

Scientist 

National Center for Atmospheric Research

Atmospheric Chemistry Observations and Modeling Laboratory

P. O. Box 3000

Boulder, CO  80307-3000

303-497-1463

[Pradeep Attri]

Hello Alma

 I am actually interested in VOCS and interested in simulating Isoprene and mainly BVOCS. can you suggest the chemistry scheme that will be better for simulating Isoprene? Some papers suggested MADE/SORGAN but i am been suggested here on the forum that MOZART-MOZAIC is the one I can use.

As i am using WRF-Chem V3.9.1.1 I can not use T1_MOZCART or can I? 

sorry, I am new to WRF-Chem I am not sure which chemistry scheme to use can you please help me ??? 

please suggest me which scheme will be better to simulate isoprene.  any help will be highly appreciable. 

Regards

Pradeep 

--

Pradeep Attri

18ESPE05

PhD Scholar

7838647455

iama...@gmail.com

18es...@uohyd.ac.in

University of Hyderabad

GachiBowli, Hyderabad

[Alma Hodzic]

Hi Pradeep

I cannot tell you which isoprene scheme performs the best, and my advice would be to run a couple of them and compare, and evaluate with measurements.

You can use MOZCART-T1 in v3911, and that version should be up-to-date; might be close to the MOZART mechanism used in https://acp.copernicus.org/articles/20/3739/2020/.

Version in MOZART-MOSAIC is comparable to https://acp.copernicus.org/articles/14/6213/2014/.

Hope that helps.

Alma

[Alma Hodzic]

So one correction, MOZCART-T1 was added in v4.0 and not in v3.9.

Alma

On Tue, Mar 16, 2021 at 6:33 AM Pradeep Attri <iama...@gmail.com> wrote: