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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. EU-QUANTIFY 2005-2010 (FP6).
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The Impact of ACARE reductions in Future Aircraft NOx Emissions on the Composition and Oxidizing Capacity of the Troposphere in 2050J. E. Williams, . Hodnebrog, P. F. J. van Velthoven and the QUANTIFY modeling team
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.
Quantify Transport Emission Estimates for NOx B1 Scenario (optimistic) : Abatement and mitigation procedures are effective Fraction 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
B1 and B1 ACARE Aircraft Emission Estimates -0.139 TgN yr-1 +0.343 TgN yr-1 +0.262 TgNyr-1 -0.408 TgNyr-1
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 2025 Relative partitioning towards Tropics increases in the Future
QUANTIFY Model Ensemble 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 sector Scaled to ~100% (Grewe et al, GMD, 2010)
NH Perturbations in O3: Ensemble model mean B1ACARE scenario only emission scenario with lower O3 than 2000 in ensemble mean Non-linearites cause 2025 to be < 2050
Global tropospheric O3 budget (TM4) 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
NH Perturbations in UTLS OH : Ensemble Mean Average between 200-300 hPa
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 areas Decreases over populated regions from Industrial and Traffic Mitigation
Impact of Air traffic emissions on air quality: 2050 B1 Aircraft Emissions fully removed : Impact on surface O3 Increases surface O3 in NH by ~1-5%
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)
Impact of ACARE emissions on Oxidising Capacity: 2050 There is a feedback in that reducing aircraft NOx increases the atmospheric lifetime of methane thus increasing the RF component Effect could be mitigated with increasing Relative Humidity due to rising Temperatures OH + CH4 (+ O2) > CH3O2 + H2O ~16% OH + CO > HO2 + H2O + CO2 ~ 40%
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.