1. Bryan Duncan, Arlene Fiore, Oliver Wild, Daniel Jacob
Chemical nonlinearities in relating intercontinental ozone pollution to anthropogenic emissions
Shiliang Wu
Bryan Duncan, Arlene Fiore, Oliver Wild, Daniel Jacob
HTAP meeting, Washington, DC
June 12, 2008
with support from the NASA/MAP program

2. NOx reduction increases the ozone production efficiency
Non-linearity in NOx perturbations (GMI – JJA) (surface ozone and changes due to perturbations in EA NOx emissions)
Control
(ppb)
EA NOx -20%
3.0
2.0
0.4
0.1
-0.1
-0.4
-2.0
-3.9 70 60 50 40 30 20 10
EA NOx = 0
Full perturb / (20% perturb x 5)
15.0
10.0
0.4
0.1
-0.1
-0.4
-2.0
-3.9
2.0
1.5
1.2
1.1
0.9
0.8
0.6
0.2
NOx reduction increases the ozone production efficiency

3. - - - - (effects from -20% NOx) x 5 ____ effects from -100% NOx
Even stronger nonlinearity in NOx perturbations for non-summer seasons (GMI)
Ozone production is most NOx-limited in summer and hence shows the best linearity
(effects from -20% NOx) x 5
____ effects from -100% NOx

4. Full perturb / (20% perturb x 5)
VOC perturbations show very good linearity (GMI – JJA) (surface ozone and changes due to perturbations in EA VOC emissions)
Control
(ppb)
EA NMVOC -20% 70 60 50 40 30 20 10
0.3
0.2
0.1
0.01
-0.01
-0.1
-0.2
-0.6
EA NMVOC = 0
Full perturb / (20% perturb x 5)
2.0
1.5
1.2
1.1
0.9
0.8
0.6
0.2
1.5
1.0
0.5
0.05
-0.05
-0.5
-1.0
-3.5

5. - - - - (effects from -20% VOC) x 5 ____ effects from -100% VOC
VOC perturbations show very good linearity for all seasons and all source-receptor pairs
Much less variability in OPE with regard to VOCs compared to NOx [Wang & Jacob, 1998]
(effects from -20% VOC) x 5
____ effects from -100% VOC

6. Nonlinearity with EU NOx perturbations - model intercomparison
EU  NA
Despite differences in ozone response magnitudes, all models show best linearity in summer.
NA O3 decrease with 0 EU NOx
EU  EA
(EA O3 decrease from -20% EU NOx) x 5
NA O3 decrease with 0 EU NOx
(NA O3 decrease from -20% EU NOx) x 5

7. Relative benefit in controlling NMVOCs vs
Relative benefit in controlling NMVOCs vs. NOx is larger with smaller magnitude of emission reductions
D (O3) from foreign NMVOC reduction
D (O3) from same % foreign NOx reduction
GMI

8. Thank you!

10. Backups

11. Nonlinearity with EU NOx perturbations – model intercomparison
EU  EU

12. Region definition
Fiore et al., 2008

13. Changes in surface ozone due to perturbations in ‘foreign’ emissions (GMI / spring)
Relative importance of NOx vs. NMVOCs in intercontinental transport depends on the magnitude of emission reductions

14. - - - - (effects from -20% NOx) x 5 effects from -100% NOx
Mutual comparison among different pairs in sensitivity to intercontinental NOx perturbations
(effects from -20% NOx) x effects from -100% NOx

15. Consistency and discrepancy across models (Changes in NA surface O3 due to changes in EU NOx emissions)
- - ( perturbations from -20% EU anthro. NOx) x 5
__ perturbations from zeroing out EU anthro. NOx
MZ = MOZART-v2 (Arlene Fiore)
FR = FRSGCUNI (Oliver wild)

16. Consistency and discrepancy across models (Changes in NA surface O3 due to changes in EU anthropogenic emissions)
- - ( perturbations from -20% all EU anthro. emis) x 5
__ perturbations from zeroing out EU anthro. emis