Hemispheric transport of ozone pollution and the nonlinearities

GMI meeting

UC Irvine

March 17, 2008

Shiliang Wu, Harvard

Bryan Duncan, NASA / GSFC

Arlene Fiore, NOAA / GFDL

Daniel Jacob, Harvard

Oliver Wild, University of Lancaster

HTAP Multi-model approach to estimate intercontinental source-receptor (S-R) relationships for ozone

20% decreases in:

anthrop. emis. in HTAP regions for NOx, CO, NMVOC individually

anthrop. emis. of all O3 and aerosol precursors in HTAP regions

global CH4

Conduct base simulations with 3-D models horizontal resolution of 4°x5° or finer 2001 meteorology each group’s best estimate for emissions in 2001 methane set to a uniform value of 1760 ppb

Conduct sensitivity simulations (17 total)

NA EUSA

EA

(Slide from Arlene Fiore @ GFDL)

Estimates of S-R relationships: Springtime surface O3 decrease in HTAP receptor regions from 20% reductions of O3 precursors

0

0.20.4

0.6

0.8

11.2

1.4

NOx VOC CO ALL

EU and NA ≥ SA

RECEPTOR = EAST ASIA

20% foreign emis.) -20% domestic emis. ≈ 85%

pp

bv

EA/EU contribute similarly

EU VOC at least as important as NOx

RECEPTOR = NORTH AMERICA

pp

bv

20% foreign emis.) -20% domestic emis. ≈ 55%

SOURCE REGIONS: 3 foreign regions

0

0.2

0.4

0.60.8

1

1.2

1.4

NOx VOC CO ALL

Larger uncertainty in role of foreign VOC

(Slide from Arlene Fiore @ GFDL)

Some questions remaining

Why so large variations across models associated with the role of VOCs?

Can 20% emission perturbations be scaled to other magnitudes? (Do the perturbations show good linearity? – this could have implications for the relative importance of different precursors in impacting the regional ozone export)

Do different models have similar/consistent linearity/nonlinearity for various perturbations?

Large variations in EU AVOC inventories across models lead to large variations in calculated ozone export from EU

y = 0.0028x + 0.0362

R2 = 0.5898

0

0.05

0.1

0.15

0.2

0.25

0 5 10 15 20 25 30 35 40 45 50

EU AVOC inventories (Tg C / yr)

An

nu

al m

ea

n s

urf

ac

e O

3 d

ec

rea

se

s o

ve

r N

A (

pp

b)

GMI

GEOS-Chem

Annual mean NA surface O3 decreases (ppb) in response to 20% EU anthro. NMVOC reductions in different models

Changes in surface O3 due to changes in EU AVOC emissions(simulation results from GMI model for JJA)

EU AVOC -20%

Full perturb / (20% perturb x 5)EU AVOC = 0

Control (ppb)

VOC perturbations are strongly linear

VOC perturbations show very good linearity for all seasons

-0.5

-0.45

-0.4

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

pe

rtu

rba

tio

ns

in O

3 (

pp

b)

(EU AVOC -20%) x 5

EU AVOC -100%

Changes in surface O3 over North America due to perturbations in EU anthro. VOC emissions (GMI results)

How about NOx?

Changes in surface O3 due to changes in EA NOx emissions (simulation results from GMI model for JJA)

EA NOx -20%

Full perturb / (20% perturb x 5)EA NOx = 0

Control (ppb)

NOx perturbations show non-linearity

Sensitivity to NOx emissions for different intercontinental pairsEA --> EUEA --> NA

-2

-1.6

-1.2

-0.8

-0.4

0

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

per

turb

atio

ns

in O

3 (p

pb

)

EU --> EAEU --> NA

-2

-1.6

-1.2

-0.8

-0.4

0

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

pe

rtu

rba

tio

ns

in O

3 (

pp

b)

NA --> EANA --> EU

-4

-3

-2

-1

0

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

pe

rtu

rba

tio

ns

in O

3 (

pp

b)

- - - - (effects from -20% NOx) x 5 effects from -100%NOx

The nonlinearities for NOx perturbations are even larger for other seasons.

Distinctive seasonal pattern for the North America impacts on Europe?

Source region: EA

Source region: NA

Source region: EU

Intercontinental influence on surface O3 for different precursors

Decrease in surface O3 (ppb) due to foreign emission reductions

0

0.5

1

1.5

2

2.5

3

3.5

4

20% reductions (HTAP models / MAM)

North America

Europe East Asia

South Asia

Fiore et al. [2008]Sensitivity to VOC comparable to NOx

0

1

2

3

4

5

6

VOC

NOx

100% reductions (GMI/MAM)

0

1

2

3

4

5

6

VOC

NOx

North America

Europe East Asia

100% reductions (GMI/JJA)

Much weaker sensitivity to

VOC compared to NOx with full reductions or in

summer

Intercontinental influence on surface O3 for different regions

Fiore et al. [2008]

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

per

turb

atio

ns

in O

3 (p

pb

)

(EU-20%)x5EU-100%(NA-20%)x5NA-100%

-3

-2.5

-2

-1.5

-1

-0.5

0

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

pe

rtu

rba

tio

ns

in O

3 (

pp

b)

(EU-20%)x5

EU-100%

(EA-20%)x5

EA-100%

Foreign impact on NA (GMI)(HTAP)

(HTAP)

EU ~ EA?

NA ~ EU

Foreign impact on EA (GMI)

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 (from Arlene)FR = FRSGCUNI (from Oliver)

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

per

turb

atio

ns

in O

3 (p

pb

)

MZ_SR3EU * 5 MZ_SR3zEU

FR_SR3EU * 5 FR_SR3zEU

GMI_SR3EU*5 GMI_SR3zEU

- - - ( perturbations from -20% all EU anthro. emis) x 5

__ perturbations from zeroing out EU anthro. emis (NOx & VOC & aerosols)

Consistency and discrepancy across models(Changes in NA surface O3 due to changes in EU anthropogenic emissions)

-2.5

-2

-1.5

-1

-0.5

0

JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN

pe

rtu

rba

tio

ns

in O

3 (

pp

b)

MZ_SR6EU * 5MZ_SR6zEUFR_SR6EU * 5FR_SR6zEU

GMI_SR6EU*5GMI_SR6zEU

On the family definition of Ox

Ox = O3 + O + NO2 + 2 NO3 + 3 N2O5 + PANs + HNO3 + HNO4

Ox = O3 + O + NO2 + 2 NO3 + 3 N2O5 + PANs + 2 HNO3 + HNO4 + other nitrates

Ox = O3 + O + NO2 + 2 NO3 + 3 N2O5 + PANs + 2 HNO3 + 2 HNO4 + HO2 + OH

…

Inconsistency in the family definition of Ox in literature on ozone budgets, leading to ambiguities in model intercomparisons.

O3

O

NO2NO3 N2O5 HNO3

RNOx

HNO4

OH

HO2/RO2

HONO

H2O2/ROOH

Transport from stratosphere

Deposition

Carbonyls

Emission

h

12

Ox family

H2O, O2

A new family definition of Ox

(Slide from Daniel Jacob)

0.51

1.523

Ox = O3 + O + NO2 + 2 NO3 + 3 N2O5 +

PANs + 1.5 HNO3 + HNO4 + 0.5 HOy

Thank you!