Transport of ozone and reactive nitrogen during INTEX-B Thomas W. Walker M. Sc. thesis defence August 30, 2007 Photo from Environment Canada OMI Tropospheric O 3 column

NO x emission O 3 production O 3 transport Trans-Pacific transport of ozone and reactive nitrogen

NO x Catalyzes Ozone Production Ozone production efficiency increases with decreasing NO x PN's (PAN, MPAN, PPN, etc...) remove NO x from source regions and redistribute it to remote regions RC(O)OO + NO 2 RC(O)OONO 2

DC-8 (red): 10 flights C-130 (blue):12 flights Cessna (green):33 flights IONS (magenta):55 sondes Data Sources and Locations

Ozone Intercomparison Cessna in red, C-130 in blue Mean bias of 2.0 ppbv

GEOS-Chem version GEOS-4 meteorological fields 4 o x5 o, 30 vertical levels NO x -O x -hydrocarbon chemistry Modifications to emissions Global CTM description

CDIAC scalars ( )‏ SCIAMACHY scalars ( )‏ Development of East Asian NO x emissions inventory 6.9 Tg yr Tg yr Tg yr Tg yr Tg yr -1

Evaluation of East Asian anthropogenic NO x emissions vs OMI: 14.3% model bias vs SCIAMACHY: 12.9% model bias r 2 > 0.8 against both instruments

Campaign average vertical profiles: O ppbv5.7 ppbv-0.5 ppbv Mean bias, observation to baseline: Increase, relative to 2000 emissions: 3.0%2.8% Aircraft Baseline (2006) ‏ Streets (2000) ‏ No Asia No Lightning

Campaign average vertical profiles: NO y Aircraft Baseline (2006) ‏ Streets (2000) ‏ No Asia No Lightning

Sonde vertical profiles: O ppbv9.1 ppbv Mean bias, observation to baseline (below 300 hPa): Aircraft Baseline (2006) ‏ Streets (2000) ‏ No Asia No Lightning

Tropospheric O 3 columns

Sources of O x production over the Pacific

Identifying transport pathways

Ozone flux into western Canada

Conclusions Remote sensing of trace gases: constrain and evaluate emissions Aircraft observations impacted by Asian anthropogenic emissions (LT) ‏ Lightning emissions (UT) ‏ Gross ozone production in E. Pacific depends on PN transport 35% of E. Pacific PN's originate in Asia >27% of O x production due to Asian PN's Events observed by aircraft Elevated O 3 (>95 ppbv), CO (>150 ppbv), and PAN (> 500 ppbv) ‏ Contributions from Asian emissions are high Flow directed northeastward, >19% from Asia

Future Directions Continued evaluation of INTEX-B in situ data Search for events indicative of transport to the Arctic Apply inverse model to constrain sensitivities to Asian source Evaluation of transport pathways using in situ and remote sensing data from ARCTAS

This work was supported by the Special Research Opportunity Program of the Natural Science and Engineering Research Council (NSERC) of Canada. Thomas Walker was supported by an NSERC Canadian Graduate Scholarship. The DC-8 and C-130 measurements were supported by NASA and NSF. Special thanks to: Randall Martin Dal's Atmospheric Composition Analysis Group INTEX-B colleagues Lauren Hughes Valerie Gapp

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Extra Slides

initiation: O 3 + hv--> O 2 + O( 1 D) ‏ O( 1 D) + M-->O + M H 2 O + O( 1 D) --> 2OH propagation: RH + OH O2 --> RO 2 + H 2 O[1] RO 2 + NO--> RO + NO 2 [2] RO + O 2 --> R'CHO + HO 2 [3] HO 2 + NO--> OH + NO 2 [4] NO 2 + hν O2 --> NO + O 3 termination: HO 2 + HO 2 --> H 2 O 2 + O 2 [5] NO 2 + OH + M--> HNO 3 + M[6] NONO 2 N2O5N2O5 HNO 3 PN NO x NO y

SCIAMACHY OMI ENVISAT, launched March :00 local overpass time Global coverage in 6 days 30km along track X 60km across track +/- (5x10 14 molec cm %) NO 2 retrieval uncertainty AURA, launched July :45 local overpass time Daily global coverage 13km X 24km at best NO 2 columns biased 15-30% low vs column measurements, 20-50% low inferred from ground measurements, and 40% lower than SCIAMACHY over industrial regions

OM I GEOS- Chem SCIAMACH Y GEOS- Chem Comparison of simulated and observed tropospheric NO2 columns