OZONE AND ITS PRECURSORS OVER THE UNITED STATES: SOURCES, OUTFLOW, TRANSPACIFIC INFLOW, AND HEMISPHERIC INFLUENCE Rynda Hudman Advisor: Daniel Jacob April 6, 2007 INTEX-B mission Houston, March 2006 Biomass burning Keeping ourselves in a job (Rob and Rama doing their part)

CONTINENT 2 OCEAN CONTINENT 1 Intercontinental Influence of Ozone (1) primary constituent of smog in surface air [NRC, 1991] (2) 3 rd most important greenhouse gas [IPCC, 2001] OHHO 2 VOCs NO NO 2 h Hemispheric Pollution Direct Intercontinental Transport (1 week) Air quality Greenhouse gas Alt (km) 10 6 Air quality O3O3

NORTH AMERICA : at midlatitudes we are all in each others tailpipe Background ozone Transpacific transport Local surface production Convection/Lightning Export Transatlantic Transport IN OUT CO is used as a tracer of pollution My work focuses on CO column GMAO Forecast Friday, 4/20/06 - Mon, 4/24/06

RISING OZONE BACKGROUND AT NORTHERN MID- LATITUDES Mountain sites in Europe Marenco et al. [1994]Jaffe et al. [2003] U.S. Pacific coastal sites What is North American impact on ozone from biomass burning, fossil fuels, and lightning?

N. America SENSITIVITY OF SIMULATED SURFACE OZONE TO ANTHROPOGENIC EMISSIONS IN INDIVIDUAL CONTINENTS Europe Asia [Li et al., 2002] Sept 1997

Regional Pollution Ozone (ppbv) Cumulative Probability Low-elevation CASTNet sites, Jun-Aug CASTNet observations GEOS-Chem model Model background * DEPLETION OF OZONE BACKGROUND DURING REGIONAL POLLUTION EPISODES How much does Asian pollution affect ozone air quality in the United States? Fiore et al., [2002]

1. INFLOW: How is ozone produced during transpacific transport of Asian pollution, and what are the implications for surface ozone air quality in the U.S.? 2. SOURCES and CHEMICAL EVOLUTION: How well constrained are U.S. CO and NO x sources from combustion and lightning? Can we relate the trend in the ozone-CO relationship in the U.S. boundary layer outflow to changes in OPE and emissions? 3.OUTFLOW AND INFLUENCE: How does NO x evolve in the U.S. boundary layer and what are the implications for NO x export? What is the impact of NA biomass burning, lightning and anthropogenic export on hemispheric ozone? RESEARCH Questions: TOOL: GEOS-CHEM: 3-D coupled ozone-NO x -VOC-aerosol tropospheric Chemistry Model [Bey et al., 2001] (uses assim. met.; 2ºx2.5º horiz. resn., 43 tracers) to interpret aircraft observations of ozone and its precursors SOURCES, OUTFLOW, TRANSPACIFIC INFLOW, AND HEMISPHERIC INFLUENCE

North America Subsidence Over E Pacific PAN  NO x  HNO 3 strong  O 3 X10 Dilution Asian Plume  Asia  Europe INFLOW MAJOR FINDINGS NO x stationary sources 22% Anthropogenic CO 60% Alt (km) 10 O 3 (ppbv) SOURCES AND EXPORT BB NA FF Lightning NO x /flash 4X larger than previously thought! Export well constrained  effects on O 3 & OPE SUMMERSPRING

North America  Asia  Europe MAJOR FINDINGS (2) North American (NA) enhancement to Northern Hemisphere summertime ozone burden Northern Hemisphere Burden 2004 NA Biomass burning enhanced ozone 2-6 ppbv over Europe! 

NOAA/ITCT-2K2 AIRCRAFT CAMPAIGN IN APRIL-MAY 2002 Monterey, CA High-ozone Asian pollution plumes observed in lower free troposphere but not at surface (Trinidad Head) CO O3O3 PAN HNO 3 May 5 plume at 6 km: High CO and PAN, no O 3 enhancement May 17 subsiding plume at 2.5 km: High CO and O 3, PAN  NO x  HNO 3 Hudman et al. [2004] T. Ryerson (O 3, NO x ), John Holloway (CO), Frank Flocke (PAN), Andy Neuman (HNO 3 ) Measurements (NOAA WP-3D):

CONCEPTUAL PICTURE OF OZONE PRODUCTION IN TRANSPACIFIC ASIAN POLLUTION PLUMES NO x HNO 3 PAN Asian boundary layer (OPE ~ 5) PAN, weak  O 3 Warm conveyor belt; 5-10% export of NO y mainly as PAN strong  O 3 Subsidence Over E Pacific Gross OPE 60-80, low OH PAN  NO x  HNO 3 U.S. boundary layer very weak  O 3 10x dilution (Asian dust data) E. Asia Pacific United States Hudman et al. [2004] Stratospheric downwelling GEOS-CHEM Hudman et al. [2004]

CALIFORNIA MOUNTAIN SITES ARE PARTICULARLY SENSITIVE TO ASIAN OZONE POLLUTION Observed 8-h ozone at Sequoia National Park (1800 m) in May 2002 vs. corresponding simulated (GEOS-CHEM) Asian pollution ozone enhancement Asian enhancements are 7-10 ppbv during NAAQS exceedances; unlike at surface sites, Asian pollution influence is not minimum under high-ozone conditions! May 17 obs. Asian plume event in red Hudman et al. [2004]

ICARTT: COORDINATED ATMOSPHERIC CHEMISTRY CAMPAIGN OVER EASTERN NORTH AMERICA AND NORTH ATLANTIC IN SUMMER 2004 SCIENTIFIC OBJECTIVES Regional Air Quality Continental Outflow Transatlantic Pollution Aerosol Radiative Forcing

Biomass burning 2004 Persistent Alaskan and Canadian burning Canadian National Forest Fire Situation Report Sept 8, 2004 ( Wildfires in Alaska: > 2,500,000 Hectares! Alaska Fire services: “The largest fire season in Alaska’s rich history ” Biomass burning inventory created using MODIS hotspots and daily area burned Canada [Turquety et al., 2007] CO June – August 2004

[Wallace McMillan]

May-August 2004 NA Fire Inventory [Turquety et. al, 2007] EPA National Emissions Inventory 1999 v1 (w/ modifications to VOCs) Power plant and Industry NOx 50% Anthropogenic CO 60% GEOS-CHEM SIMULATION NOx Lightning Emissions Lightning X4 over U.S. & distributed to tropopause [Price and Rind, 1992] Modifications from ICARTT constraints in blue (improved) Flash counts (flashes/km 2 /s) CO emissions NO x emission

GEOS-CHEM VS. ICARTT Mean comparison along the flight tracks Large UT NO x bias BL bias in CO and NO x Ozone FT bias 5-10 ppbv Measurements (WP-3D, DC-8): CO (J. Holloway, G. Sachse), NO x (T. Ryerson, R. Cohen, W. Brune), PAN (F. Flocke, H. Singh), HNO 3 (A. Neuman, J. Dibb), ozone (T. Ryerson, M. Avery)

Observed Simulated Improved Simulation DC-8 Midwest Model / Observed NO x (0-2 km) Hudman et al. [2007a,b] [ratio] Large overestimate powerplant/industry dominated Midwest and in the South 50% reduction in power and industry source as determined by Frost et al., [2006] improves boundary layer NO 2 simulation ICARTT OBSERVATIONS CONFIRM LARGE DECREASE SINCE 1999 IN INDUSTRY/POWER SOURCE Measurements (WP-3D, DC-8): T. Ryerson (NO 2 ), Ron Cohen/Tim Bertram (NO 2 )

OZONE REDUCTIONS RESULTING FROM DECREASE IN NO x EMISSIONS Can we see changes in OPE due NO x emission reductions in dO 3 /dCO in U.S. outflow? Requires good estimate of CO source….. Regional differences in  ozone, can be explained by OPE: OPE Midwest: Southeast: Hudman et al. [2007b]

Measurments: J. Holloway, G. Sachse, A. Goldstein BOTH AIRCRAFT AND SURFACE DATA SUGGEST NEI 99 CO EMISSIONS ARE 2.5 TIMES TOO HIGH Aircraft (0-1.5 km) Chebogue Point (surface) OBSERVED SIMULATED (NEI99 ) SIMULATED (anthro CO reduced by 60%) Measurments: J. Holloway, G. Sachse Measurments: A. Goldstein/ Dylan Millet Hudman et al. [2007b]

SCATTERPLOT OF SIMULATED TO OBSERVED CO Parrish [2006] finds on-road source overestimated by 50% in NEI 99 (  ~33% reduction in NEI source) CO decrease trend 3.7% yr - 1 ( ), (  12% reduction in NEI source since 1999)  This estimate 2004 emissions 45% lower than NEI 99 Hudman et al. [2007b]

ANTHROPOGENIC CO SOURCE IN THE UNITED STATES IN SUMMER IS NOW LOWER THAN BIOGENIC SOURCE CO ANTHROPOGENIC EMISSION (11.5, 4.6) CO SOURCE FROM ANTHROPOGENIC VOC OXIDATION (1.8, 1.8) CO SOURCE FROM ISOPRENE OXIDATION (6.7, 6.7) CO SOURCE FROM OTHER BIOGENIC OXIDATION (2.4, 2.4) NEI 99NEI 99 with 60% reduction in CO CO SOURCE FROM OTHER BIOMASS BURNING OVER CONTINENTAL U.S.(0.16, 0.16)  Note: Fires in Canada and Alaska ~19 Tg CO SOURCE TYPE (Tg CO)

OZONE-CO CORRELATIONS SHOW DECADAL INCREASE Obs during the early 90s show dO 3 /dCO ~ 0.3 – 0.4 [Chin et al., 1994; Parrish et al., 1998]. Change could be due to decadal changes in emissions Overestimate of tropical background WINDS FROM W-SE ALL WIND DIRECTIONS Aircraft (0-1.5 km, 11-5pm LT) Chebogue Point Hudman et al. [2007b]

OBSERVED dO 3 /dCO INCREASE OVER THE PAST DECADE CONSISTENT WITH UNDERSTANDING OF OPE AND SOURCES dO 3 /dCO  OPE (dO 3 /dNOx) * NO x /CO source ratio (dNO x /dCO ) Consider NE U.S., July 1 – August 15, 2004 (With ICARTT Constraints) Anthro = 1.2 Tg CO, 0.10 Tg N Biogenic = 0.87 Tg CO July 1 – August % anthro decrease/year in urban air [Parrish, 2006]  Total CO 26% higher 22% stationary NO x reduction [Hudman et al., 2007]  Anthro NO x 15% higher  OPE lower by ~9%  NO x /CO source ratio lower by ~19% ~28% increase in dO 3 /dCO expected (90s)  (present) Multiply dO 3 /dCO * ECO  1.5 Gmol ozone d -1 ( Ozone flux consistent with 1990s estimates)

SPECIATION AND EXPORT OF BOUNDARY LAYER NO x Hudman et al. [2007a] We find observed f = 16  10% and modeled f = 14  9% ( km) Model successfully simulates boundary layer NO y OBSERVEDGEOS-Chem NO x HNO 3 PAN f= export efficiency R = ECO anthro /ENO xanthro  = NMVOC CO production Export to the lower free troposphere is mostly HNO 3 but at higher altitudes is mostly PAN. 18%7% 20%9% 62%84% Offshore %Onshore %

UT NO x OBSERVATIONS POINT TO A LARGER THAN EXPECTED LIGHTNING NO x SOURCE Hudman et al. [2007a] GEOS-Chem (Lightning X4)Observed NO x (8-12 km) [ppbv] DOESN’T APPEAR TO BE A NO x LIFETIME ISSUE NO: W. Brune, NO 2 : R. Cohen/T Bertram

Lightning parameterization (flashes/km 2 /s): Land : ~CTH 4.9, Ocean: ~CTH 1.73 CTH= Cloud Top Height Price and Rind [1992] GEOS-Chem Vertical Distribution GEOS-Chem NLDN [ Flashes km 2 s] FLASH RATES WELL SIMULATED POINTING TO A LARGER YIELD/FLASH AT NORTHERN MIDLATITUDES Flash Comparison Pickering et al., [1998] Hudman et al. [2007a]

[Huntrieser et al., 2005] PEAK CURRENT AS A FUNCTION OF LATITUDE

[Ken Pickering] NO PRODUCTION RATE CALCULATED FROMR RECENT CAMPAIGNS Standard GEOS-Chem mean flash rate was 125 mol flash -1 (Improved  X4  500 mol flash -1 )

OZONE COMPARISON INTEX-NA SOUTHEAST U.S. Increase in lightning yield X4 to 500 mol/flash has ~10 ppbv effect on ozone NO 2 O3O3 Hudman et al. [2007a] …suggests great sensitivity of ozone to climate change Observed Simulated Improved Simulation 2004 was not an anomalous lightning year

Hudman et al. [2007b] SUMMERTIME NORTH AMERICAN OZONE ENHANCEMENTS Biomass Lightning Anthropogenic Simulated Observed All North American Source NO x Emission (Tg N) Ozone Production Efficiency Hemispheric ozone enhancement (Tg, %) Lightning (5.1%) Biomass burning (3.1%) Fossil fuel (6.1 %) All (14.3 %) NA Enhancement to Hemispheric Ozone ICARTT DC-8 ~ Equal contributions for lightning and anthropogenic emissions in free troposphere and to NH burden

Hudman et al. [2007b] NORTH AMERICAN ENHANCEMENT TO HEMISPHERIC OZONE

1. PAN decomposition represents a major and possibly dominant component of the ozone enhancement in transpacific Asian pollution plumes. 2.A factor of 10 dilution of Asian pollution plumes takes place during entrainment in the U.S. boundary layer, greatly reducing their impact at U.S. surface sites. 3.California mountain sites are more sensitive to Asian pollution because of their exposure to the free troposphere. Asian enhancements are 7-10 ppbv during NAAQS exceedances; unlike at surface sites, Asian pollution influence is not minimum under high-ozone conditions. 4.A 50% summertime powerplant/industry NO x reduction source 1999 results in an 4 – 8 ppbv reduction in ozone at the surface with maximum effect in the southeast. 5.Anthropogenic CO emission in NEI 99 is overestimated by 60%. 6.The biogenic CO source now exceeds the anthropogenic source in summer. MAJOR FINDINGS (1)

7. dO 3 /dCO in NA boundary layer outflow is ~28% higher than in the early 1990s, consistent withour understanding of changes in OPE and emissions. 8. Lightning is the dominant source of UT NO x over United States during the summer and had ~10 ppbv impact on upper tropospheric ozone. 9. Successful simulation of lightning over the U.S. requires a factor of 4 increase in NO x yield to 500 mol flash Lightning & Anthropogenic emissions each enhance ozone by ppbv in the upper free troposphere over the U.S. Biomass burning enhancement over the Eastern U.S. was greatest below 4 km (~3-4 ppbv). 11. Lightning & anthropogenic emissions have a roughly equal enhancement to hemispheric ozone (~5%) during the summer. 12. Biomass burning emissions enhance surface ozone over Western Europe by 3-5 ppbv, comparable to the enhancement from fossil fuel. MAJOR FINDINGS (2)

Acknowledgements -I would like to whole-heartedly thank my advisor, Daniel Jacob, who is a brilliant scientist, patient mentor, and a good person. -The research group (past and present) + Justin, Jenny, Peter, Moeko Disclaimer: I am not leaving "If you light a lantern for another, it will also brighten your own way" -- Nichiren Daishonin (Gosho Zenshu, p. 1598).

More Acknowledgements Disclaimer: I am not leaving -“THANKS” Lee Murray - Bob Yantosca, Jack Yatteau, and Phillipe Le Sager -Brenda Mathieu, Cecilia McCormack -Dylan Millet, Colette Heald, Soléne Turquety, Lin Zhang, Folkert Boersma, Qinbin Li, Lyatt Jaeglé, Qing Liang, Mat Evans - ITCT 2k2/PEACE, ICARTT, INTEX-B Science Teams…in particular Yutaka Kondo, Jim Crawford, Hanwant Singh, David Parrish, Owen Cooper - Jennifer Logan and Loretta Mickley (New bosses) - NSF and AMS/NOAA graduate fellowships **This work was funded by NOAA Office of Global Programs, NASA Global Tropospheric Chemistry Program

Even more Acknowledgements -My mom and Henry a constant source of support and love. The rest of my family! -Rob Kay (Thanks for coming Penny and Mark!) -Some dear friends: Debbie Sorenson, Nenita Elphick, Julie Schlenker, May Fu, Monika Kopacz, Colette Heald, Noelle Eckley, Mary Farrow, Yaping Xiao -My great friends in the SGI-USA & World Peace Buddhist Society campus club Disclaimer: I am not leaving

[