J. E. Williams, ACCRI, 22-02-11

The Impact of ACARE reductions in Future Aircraft NOx Emissions on the Composition and Oxidizing Capacity of the Troposphere in 2050

J. E. Williams, . Hodnebrog, P. F. J. van Velthoven and the QUANTIFY modeling team

J. E. Williams, ACCRI, 22-02-11

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EU-QUANTIFY 2005-2010 (FP6)

Quantifying the Climate Impact of Global and European Transport Systems

www.pa.op.dlr.de/quantify

Emission datasets used in this study available on the site

Activity 3: Large-scale Chemistry Effects

Related Publications:

P. Hoor, et al., The impact of traffic emissions on atmospheric ozone and OH: results from QUANTIFY, Atms. Chem. Phys., 9, 3113-3136, 2009. (Preliminary Emission Estimates)

G. Myhre et al., Radiative forcing due to changes in ozone and methane caused by the transport sector, Atms. Environ., 45, 387-394, 2011.

O. Hodnebrog et al., Future Impact of non-land based traffic emissions on atmospheric ozone and OH – an optimistic scenario and a possible mitigation strategy, in preparation.

J. E. Williams, ACCRI, 22-02-11

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Quantify Transport Emission Estimates for NOx

B1 Scenario (optimistic) : Abatement and mitigation procedures are effectiveFraction of NOx from air decreases for ACARE Scenario

Warming potential per NOx from AIR highest due to release in the UTLS (Fuglestvedt et al., 2008)ACARE : Advisory Council for Aeronautical Research in Europe

J. E. Williams, ACCRI, 22-02-11

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B1 and B1 ACARE Aircraft Emission Estimates

+0.343 TgN yr-1 -0.139 TgN yr-1

+0.262 TgN yr-1 -0.408 TgN yr-1

J. E. Williams, ACCRI, 22-02-11

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Variability in the Latitudinal Distribution of B1 Aircraft NOx emissions

Gg N yr-1

Growth in air NOx in Tropics between 2000 – 2050; Peak in NH at 2025Relative partitioning towards Tropics increases in the Future

J. E. Williams, ACCRI, 22-02-11

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QUANTIFY Model EnsembleModel (Institute) Hor. Res Levels Chemical Species

(Trans./Total.)Reactions

TM4 (KNMI, NL) 3° x 2° 34 (0.1) 26/42 (Trop) 68

p-TOMCAT (UCAM-DCHEM, UK)

2° x 2° 31 (10) 35/51 (Trop) 112

OsloCTM2 (UiO, Norway)

T42 60 (0.1) 76/98 (Trop/Strat) 163

LMDz-INCA (LSCE, Fr) 3.75° x 2.5° 19 (3) 66/96 (Trop) 291

UCI CTM (UCI, US) T42 37 (2) 28/38 (Trop/LINOZ) 90

MOCAGE (Meteo-France, Fr)

2° x 2° 47 (5) 89/30 (Trop/Strat)

ECMWF OD meteorology for 2003 used throughout. 5 CTMs and 1CCM. Background CH4 increased according to projections.

Experimental Methodology: 5% perturbation in Emissions from each transport sectorScaled to ~100% (Grewe et al, GMD, 2010)

J. E. Williams, ACCRI, 22-02-11

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NH Perturbations in O3: Ensemble model mean

B1ACARE scenario only emission scenario with lower O3 than 2000 in ensemble meanNon-linearites cause 2025 to be < 2050

J. E. Williams, ACCRI, 22-02-11

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Global tropospheric O3 budget (TM4)

Tg O3 yr-1 2003 2050 B1 2050 B1 ACARE

Total NOx Emissions

(Tg N yr-1)

54.5 50.1 49.8

Chemical Production 4433.6 4617.3 (+4.1%) 4586.1 (+3.4%)

Chemical Destruction 4294.8 4447.0 (+3.5%) 4418.8 (+2.9%)

Dry Deposition 669.1 779.4 (+16.5%) 696.2 (+4.1%)

Strat-Trop exchange 528.5 536.1 (+1.4%) 526.4 (-0.3%)

Trop. Burden/Lifetime 302 (22.2) 329 (23.4) 328 (23.4)

Although Total NOx emissions ~8% in B1 net chemical O3 prod. 0.6% (0.5% w/ ACARE)

Increases in Air traffic in Tropics compensate for Global NOx reduction

J. E. Williams, ACCRI, 22-02-11

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NH Perturbations in UTLS OH : Ensemble Mean

Average between 200-300 hPa

J. E. Williams, ACCRI, 22-02-11

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Influence on Surface Air Quality: 2003 vs 2050 B1

BO3 : 25 Tg (+5.4%) ; BCO : 42 Tg (-7.5%) ; BCH4 : 1425Tg (+37.6%)NO + CH3O2 NO2 O3

Background [O3] increases by ~5-10% in Pristine areasDecreases over populated regions from Industrial and Traffic Mitigation

J. E. Williams, ACCRI, 22-02-11

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Impact of Air traffic emissions on air quality: 2050 B1

Aircraft Emissions fully removed : Impact on surface O3Increases surface O3 in NH by ~1-5%

J. E. Williams, ACCRI, 22-02-11

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Impact of ACARE emissions on air quality: 2050 B1

ACARE emissions surface [O3] by ~0.5-2% in NH as a result of ACARE NOx reductions Mitigates increases in background [O3] due to CH4 (enhanced NOx recycling)

J. E. Williams, ACCRI, 22-02-11

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Impact of ACARE emissions on Oxidising Capacity: 2050

2003 2050 B1

2050 B1

ACARE

τ(CH4)

yrs

7.96 8.57 8.61

τ(CO) months

1.42 1.45 1.46

OH + CH4 (+ O2) > CH3O2 + H2O ~16%OH + CO > HO2 + H2O + CO2 ~ 40%

There is a feedback in that reducing aircraft NOxincreases the atmospheric lifetime of methane

thus increasing the RF component

Effect could be mitigated with increasing Relative Humidity due to rising Temperatures

J. E. Williams, ACCRI, 22-02-11

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Radiative Forcing from ΔO3, ΔCH4 and CH4-induced ΔO3

RF (mW m-2) ΔO3 ΔCH4 CH4-induced ΔO3 Total

2050 B1 26.2 (9.0) -17.8 (4.0) -6.5 (1.5) 1.9 (6.4)

2050 B1 ACARE

18.9 (6.8) -14.3 (3.4) -5.2 (1.2) -0.6 (4.6)

J. E. Williams, ACCRI, 22-02-11

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Conclusions• Future aircraft emissions peak in 2025 for NH and 2050 for the Tropics in B1 Scenario.

• There is a seasonal dependency in the magnitude of effects, where strong photolytic activity amplifies differences.

• Aircraft emissions contribute ~1-5% towards surface O3 in 2050 for the B1 Emission Scenario.

• Introducing ACARE Technology has the potential to reduce surface O3 ~1-2%.

• Introducing ACARE Technology changes the RF potential from slightly +ve to slightly –ve, although the std. dev. in the model ensemble is large.