INTERCONTINENTAL TRANSPORT OF TROPOSPHERIC OZONE AND PRECURSORS AT NORTHERN MIDLATITUDES: IMPLICATIONS FOR SURFACE AIR QUALITY AND GLOBAL CHANGE Daniel J. Jacob, Arlene M. Fiore, Qinbin Li, Loretta J. Mickley Atmospheric Chemistry Modeling Group Harvard University

OZONE TREND AT EUROPEAN MOUNTAIN SITES, Preindustrial ozone models } Marenco et al. [1994]

8-h daily maximum ozone probability distribution at rural U.S. sites [Lin et al., 2000] SURFACE OZONE IN U.S. INCLUDES A ppbv BACKGROUND THAT HAS INCREASED BY ~3 ppbv OVER THE PAST 20 YEARS

THIS OZONE BACKGROUND IS A SIZABLE INCREMENT TOWARDS VIOLATION OF U.S. AIR QUALITY STANDARDS (even more so in Europe!) ppbv Europe (seasonal) U.S. (8-h avg.) U.S. (1-h avg.) preindustrial present background Europe (8-h avg.)

Simulated increase in mean U.S. surface ozone (ppbv) from tripling of Asian emissions (1985 to 2015) with other emissions held constant Enough to offset the benefits of 25% reductions in domestic emissions! Jacob et al. [1999]

GEOS-CHEM global model of tropospheric chemistry (www-as.harvard.edu/chemistry/trop/geos) assimilated meteorological data from NASA DAO, o x1 o - 4 o x5 o horizontal resolution, layers in vertical used by groups at Harvard, Duke, U. Washington, Rutgers, JPL, BNL, EPFL, Toulouse, Aquila; standard versions and benchmarks maintained at Harvard RECENT AND CURRENT APPLICATIONS: –Tropospheric ozone : global budget, Asian outflow, U.S. air quality, Middle East, transatlantic transport, tropics (TOMS), interannual variability, trends –Carbon monoxide: global and regional budgets, interannual variability –Aerosols: sulfate-organics-dust-sea salt –Stratospheric ozone: coupling with troposphere –Carbon dioxide: source/sink information from correlations with chemical tracers –Organics: budgets of hydrocarbons, oxygenated organics, nitriles, methyl halides –Satellite retrievals, inversions, chemical data assimilation: CO, CO 2, ozone, formaldehyde, NO 2 –Chemical forecasting: TRACE-P

SUMMER 1995 AFTERNOON OZONE IN SURFACE AIR AIRS observations GEOS-CHEM (r 2 = 0.4, bias=3 ppbv) Fiore et al. [2001] “Background ozone” produced outside the North American boundary layer contributes ppbv to mean surface air concentrations in the model

OZONE BACKGROUND OVER U.S. IS GENERALLY DEPLETED DURING REGIONAL POLLUTION EPISODES due to deposition and chemical loss under stagnant conditions Background (clean conditions) O 3 vs. (NO y -NO x ) At Harvard Forest, Massachusetts Background (pollution episodes) Observed (J.W. Munger) model (GEOS-CHEM) model background Pollution coordinate Fiore et al. [2001]

RANGE OF ASIAN/EUROPEAN POLLUTION SURFACE OZONE ENHANCEMENTS OVER THE U.S. IN SUMMER as determined from a simulation with these emissions shut off Max Asian/European pollution enhancements (up to 14 ppbv) occur at intermediate ozone levels (50-70 ppbv) MAJOR CONCERN IF OZONE STANDARD WERE TO DECREASE! Fiore et al. [2001] tropical air Subsidence of Asian pollution + local production stagnation

NORTH AMERICAN OZONE OUTFLOW IN SURFACE AIR (GEOS-CHEM model results for 1997) Li et al. [2001] APRIL JULY L H H L

ORIGIN OF SURFACE OZONE AT BERMUDA IN SPRING Li et al. [2001] Production over U.S. is the dominant source of ozone at Bermuda; stratosphere contributes less than 5 ppbv ( S. Oltmans)

EFFECT OF NORTH AMERICAN SOURCES ON VIOLATIONS OF EUROPEAN AIR QUALITY STANDARD (55 ppbv, 8-h average) GEOS-CHEM model results, summer 1997 Number of violation days (out of 92) # of violation days that would not have been in absence of N.American emissions Li et al. [2001]

OZONE DATA AT MACE HEAD, IRELAND Observed [Simmonds] GEOS-CHEM model N.America pollution events in model Time series, Mar-Aug 1997 Model vs. observed stats, Li et al. [2001]

FORECASTING TRANSATLANTIC TRANSPORT OF NORTH AMERICAN POLLUTION TO EUROPE FROM THE NORTH ATLANTIC OSCILLATION (NAO) INDEX NAO Index North American ozone pollution enhancement At Mace Head, Ireland (GEOS-CHEM model) r = 0.57 NAO index = normalized surface P anomaly between Iceland and Azores Li et al. [2001] Greenhouse warming  NAO index shift  change in transatlantic transport of pollution

SURFACE OZONE ENHANCEMENTS CAUSED BY ANTHROPOGENIC EMISSIONS FROM DIFFERENT CONTINENTS GEOS-CHEM model, July 1997 North America Europe Asia Li et al. [2001]

To quantify the North American import and export of (1) atmospheric oxidants and their precursors, (2) aerosols and their precursors, (3) long-lived greenhouse gases To relate this import/export to surface sources/sinks and to continental boundary layer chemistry INTERCONTINENTAL TRANSPORT EXPERIMENT – NORTH AMERICA (INTEX-NA) OBJECTIVES: TWO PHASES: Summer 2004: -active photochemistry, biosphere -aerosol radiative forcing -carbon uptake Spring 2006: -maximum Asian inflow -contrast with summer TWO AIRCRAFT: NASA DC-8 and P-3 Revised white paper, Nov 2001 (H.B. Singh, D.J. Jacob, L. Pfister)

INTEGRATION OF AIRCRAFT OBSERVATIONS WITH SATELLITE DATA AND MODEL INFORMATION IS CRITICAL TO THE OBJECTIVES OF INTEX-NA 3-D CHEMICAL TRACER MODELS U.S IMPORT/EXPORT SATELLITE OBSERVATIONS Global and continuous but few species, low resolution AIRCRAFT OBSERVATIONS High resolution, targeted flights provide snapshots with optimized information SURFACE OBSERVATIONS high resolution but spatially limited Source/sink inventories Assimilated meteorological data Chemical and aerosol processes

DR RL BG BR AZ WL DC-8 P-3B HI NO Ozonesonde sites INTEX NOMINAL FLIGHT TRACKS FOR PHASE A (SUMMER)

SATELLITE MEASUREMENTS OF TROPOSPHERIC CHEMISTRY

MOPITT validation: 40N, 132W 0226 at 2005Z; double spiral bracketing in time the MOPITT overpass. Solid stratus deck with tops at 3.5Kft, otherwise clear sky. Layer at 4-7 km is aged Asian pollution. DC-8 CO data (Sachse)

ATMOSPHERIC COLUMNS OF NO 2 AND FORMALDEHYDE (HCHO) MEASURED FROM GOME BY SOLAR BACKSCATTER ALLOW MAPPING OF NO x AND HYDROCARBON EMISSIONS Emission NO h (420 nm) O 3, RO 2 NO 2 HNO 3 1 day NITROGEN OXIDES (NO x )NON-METHANE HYDROCARBONS Emission NMHC OH HCHO h (340 nm) hours CO hours BOUNDARY LAYER ~ 2 km Tropospheric NO 2 column ~ E NOx Tropospheric HCHO column ~ E NMHC Deposition GOME

CAN WE USE GOME TO ESTIMATE NO x EMISSIONS? TEST IN U.S. WHERE GOOD A PRIORI EXISTS Comparison of GOME retrieval (July 1996) to GEOS-CHEM model fields using EPA emission inventory for NO x GOME GEOS-CHEM (EPA emissions) BIAS = +3% R = 0.79 Martin et al. [2001]

GOME RETRIEVAL OF TROPOSPHERIC NO 2 vs. GEOS-CHEM SIMULATION (July 1996) GEIA emissions scaled to 1996 Martin et al. [2001]

FORMALDEHYDE COLUMNS FROM GOME: July 1996 means BIOGENIC ISOPRENE IS THE MAIN SOURCE OF HCHO IN U.S. IN SUMMER Palmer et al. [2001]

GOME DETECTS THE ISOPRENE “VOLCANO” IN THE OZARKS Palmer et al. [2001]

DEPENDENCE OF GOME HCHO COLUMNS OVER THE OZARKS ON SURFACE AIR TEMPERATURE Temperature dependence of isoprene emission (GEIA) Palmer et al. [2001b]

MAPPING OF ISOPRENE EMISSIONS FOR JULY 1996 BY SCALING OF GOME FORMALDEHYDE COLUMNS [Palmer et al., 2001b] GEIA (IGAC inventory) BEIS2 (official EPA inventory) GOME COMPARE TO…

radiative forcing from tropospheric ozone is less well constrained than implied by IPCC 2001 report Standard model: F = 0.44 W m -2 “Adjusted” model (lightning and soil NOx decreased, biogenic hydrocarbons increased): F = 0.80 W m -2 [Mickley et al., 2001] Global simulation of late 19 th century ozone observations with the GISS GCM

GLOBAL MEAN TEMPERATURE CHANGE SINCE 1750 DRIVEN BY MODEL TROPOSPHERIC OZONE CHANGE Loretta Mickley, In preparation and compared to temperature changes from equal radiative forcings (0.45 W m -2 ) by uniformly mixed ozone and CO 2 (GISS GCM 2’) Ozone Uniform ozone CO 2 Compared to an equivalent CO 2 radiative forcing, tropospheric ozone gives less tropospheric warming and more stratospheric cooling

ONGOING WORK AT HARVARD FOR PHASE I OF OAR/OAQPS CLIMATE CHANGE MODELING INITIATIVE (Arlene Fiore, Brendan Field, Daniel Jacob, David Streets) OBJECTIVE: Determine the global impacts of future changes in anthropogenic emissions on  surface ozone in N. America, Europe, and Asia;  surface ozone background;  tropospheric oxidizing capacity;  radiative forcing (CH 4 and O 3 ). APPROACH: Conduct global GEOS-CHEM simulations with 50% global reductions in emissions; realistic future emission scenarios Simulations are for 7/94-12/95 (first 6 mos. for initialization) with 4 o x5 o resolution

DiagnosticStandard50% CH 4 50% NO x 50% VOC 50% NO x & VOC 50% CO 50% All Median U.S. O 3 (ppbv) U.S. grid-square days with 1-5 p.m. O 3 >80 ppbv U.S. grid-square-days with 1-5 p.m. O 3 >60 ppbv Mean U.S. 1 background O 3 (ppbv) Global tropospheric O 3 inventory (Tg) Implied global CH 4 concentration (ppbv) CH 4 radiative forcing (W m -2 ) O 3 radiative forcing (W m -2 ) o x5 o GEOS-CHEM model results for JJA 1995 IMPACTS OF 50% REDUCTIONS IN ANTHROPOGENIC EMISSIONS

StatisticMAQSIPAIRS on MAQSIP grid GEOS-CHEM 2° x 2.5° AIRS on GEOS- CHEM grid Mean (ppbv) Variance (ppbv 2 ) Minimum (ppbv) Maximum (ppbv) Model bias (ppbv) 4--7 r 2 (model vs. observed) GLOBAL MODEL LIMITATIONS FOR SIMULATIONS OF REGIONAL OZONE POLLUTION: Comparison of GEOS-CHEM (2 o x2.5 o ) and MAQSIP (40x40 km 2 ) spatial statistics of summer means over eastern U.S. for summer 1995

Varimax rotated EOFs for surface ozone: summer afternoon 1995 AIRS observations on 2 o x2.5 o grid - cold fronts - midwest  northeast - southeast stagnation

EOFr2r2 b Correlation with EOFs derived from observations Varimax rotated EOFs for surface ozone: summer afternoon 1995 GEOS-CHEM model results

NEXT STEP: NESTING OF GEOS-CHEM WITH MODELS-3 collaboration with OAQPS and ORD One-way nesting: use GEOS-CHEM global model fields as time- dependent boundary conditions for simulation of ozone, aerosols, and their precursors in Models-3 –First application: Texas 2000 field campaign Two-way nesting: develop better simulation of regional effects on global atmospheric chemistry

SOME ISSUES FOR PHASE II OF OAR/OAQPS CLIMATE CHANGE MODELING INITIATIVE How can we develop an accurate modeling framework to address consistently local surface air quality and global change issues? –Development of nested models How can we extract information from satellite observations on intercontinental transport of pollution? –Integration with in situ observations and models, development of inverse modeling tools How does photochemical coupling between aerosols and chemistry affect assessments of emission changes on surface air quality and global change issues? –Development of coupled aerosol-chemistry models