Question about CMAQ5.2 HDDM sensitivity to multiple precursor emissions

CMAQ-DDM-3D
1

Hello,
With CMAQ 5.2 HDDM we are able to calculate O3 first and second order sensitivities to NOx (NO, NO2) and VOC emissions. Based on the result we can estimate how much emission reduction of NOx and VOC or both in an area to be attaining the ozone standard.
However, we remove all ozone precursor emissions including NOx, VOC, CO, CH4, SO2 (indirect ozone precursor via chemistry processes), not only NOx and VOC (even though those two are the most important ozone precursors) when we reduce emissions sources according to emission categories such as onroad, nonroad, and area sources. To consider sensitivity to all precursor emissions, how do we configure higher order sensitivities to more than two sensitivity parameters EMISNOX, EMISNVOC, and EMISNCO as shown in the attached sensinput.dat? Do we need to calculate the second order terms in the Taylor series expansion which takes into account second order sensitivities for all sensitivity parameters?

I will appreciate your help.

sensinput.dat file


EMISNOX
 EMIS
  GRID
  1
  EGRIDFILE1
  PT3D
  2
  PT3DSTACK1
  PT3DFILE1
  PT3DSTACK2
  PT3DFILE2
 SPECIES
  NO
  NO2

EMISNCO
 EMIS
  GRID
  1
  EGRIDFILE1
  PT3D
  2
  PT3DSTACK1
  PT3DFILE1
  PT3DSTACK2
  PT3DFILE2
 SPECIES
  CO

EMISNCH4
 EMIS
  GRID
  1
  EGRIDFILE1
  PT3D
  2
  PT3DSTACK1
  PT3DFILE1
  PT3DSTACK2
  PT3DFILE2
 SPECIES
  CH4
EMISSO2     
 EMIS
  GRID
  1
  EGRIDFILE1
  PT3D
  2
  PT3DSTACK1
  PT3DFILE1
  PT3DSTACK2
  PT3DFILE2
 SPECIES
  SO2

EMISNVOC
 EMIS
  GRID
  1
  EGRIDFILE1
  PT3D
  2
  PT3DSTACK1
  PT3DFILE1
  PT3DSTACK2
  PT3DFILE2
 SPECIES
     ALD2
  ALDX
  ETH
  ETHA
  ETOH
  FORM
  IOLE
  ISOP
  MEOH
  OLE
  PAR
...
...

2ENOX
  HIGH
  EMISNOX
  EMISNOX

2EVOC
  HIGH
  EMISVOC
  EMISVOC

2ECO
  HIGH
  EMISCO
  EMISCO

2EALL  (how to set up high cross order here?)
   HIGH
   EMISNOX
   EMISVOC
   EMISCO
2

You can calculate 2nd order sensitivity coefficients to each 1st order parameter you have defined. You can also compute “cross” 2nd order to 2 different 1st order parameters. How exactly you need to do that is for you to decide in the context of your research project.

Sergey