FACTORS CONTROLLING TROPOSPHERIC OZONE AND ITS COUPLING FROM REGIONAL TO GLOBAL SCALES

1. FACTORS CONTROLLING TROPOSPHERIC OZONE AND ITS COUPLING FROM REGIONAL TO GLOBAL SCALES Daniel J. Jacob Harvard University with support from NASA, NOAA, EPA, EPRI

2. GLOBAL BUDGET OF TROPOSPHERIC OZONE Global sources and sinks, Tg O3 yr-1 (GEOS-CHEM) O2 hn O3 STRATOSPHERE 8-18 km TROPOSPHERE hn NO2 NO O3 hn, H2O OH HO2 H2O2 Deposition CO, VOC

3. TREND IN TROPOSPHERIC OZONE BACKGROUNDAT NORTHERN MIDLATITUDES Observations from European mountain sites [Marenco et al., 1994]

4. THIS OZONE BACKGROUND IS A LARGE INCREMENT TOWARDS VIOLATION OF AIR QUALITY STANDARDS Europe (8-h avg.) Europe (seasonal) U.S. (8-h avg.) U.S. (1-h avg.) 0 20 40 60 80 100 120 ppbv preindustrial present background

5. Ozonesonde and MOZAIC observations at 400 hPa, July 1997 GLOBAL TRANSPORT OF TROPOSPHERIC OZONEAROUND THE NORTHERN MIDLATITUDES POLLUTION BELT Li et al. [2001] How does this intercontinental transport of ozone contribute to regional air quality issues?

6. SUMMER 1995 MEAN AFTERNOON OZONE IN SURFACE AIR Fiore et al. [2002a] AIRS observations GEOS-CHEM model (r2 = 0.4, bias=3 ppbv) “Background ozone” produced outside the North American boundary layer contributes 15-35 ppbv to mean surface air concentrations in the model

7. Subsidence of Asian pollution + local production stagnation tropical air U.S. standard European standards SURFACE OZONE ENHANCEMENTS OVER U.S. IN SUMMERDUE TO ASIAN & EUROPEAN ANTHROPOGENIC EMISSIONSGlobal 3-D model results (GEOS-CHEM) sampled for ensemble of summer days over the U.S. Fiore et al. [2002a]

8. NORTH AMERICAN OZONE OUTFLOW IN SURFACE AIR (GEOS-CHEM model results for 1997) L APRIL H L JULY H Li et al. [2002a]

9. TRANSPORT OF U.S. OZONE POLLUTIONTO BERMUDA IN SPRING Observations (S. Oltmans) GEOS-CHEM model (S. Oltmans) Most of surface ozone over Bermuda in spring originates from the U.S.; stratosphere contributes less than 5 ppbv Li et al. [2002b]

10. GEOS-CHEM model N.America pollution events in model Observed [Simmonds] North American pollution events enhance ozone by 5-15 ppbv OZONE AT MACE HEAD, IRELAND (Mar-Aug ’97) Li et al. [2002b]

11. TRANSPORT OF U.S. POLLUTION TO EUROPE:CORRELATION WITH THE NAO INDEX NAO index = normalized surface P anomaly between Iceland and Azores North Atlantic Oscillation (NAO) Index North American ozone pollution enhancement At Mace Head, Ireland (GEOS-CHEM model) r = 0.57 Li et al. [2002a] Greenhouse warming a NAO index shift a change in transatlantic transport of pollution

12. SPRINGTIME ENHANCEMENT OF OZONE OVER ASIADUE TO EUROPEAN ANTHROPOGENIC EMISSIONS GEOS-CHEM model results at 900 hPa, March-May 1996 Liu et al. [2002]

13. 50% NOx 2030 A1 2030 B1 50% CH4 50% CH4 50% NOx 2030 A1 2030 B1 1995 (base) 50% NMVOC 50% NMVOC Combined effects of future anthropogenic emission trendson U.S. ozone air quality and on global climate Ozone pollution Fiore et al. [2002b]

14. NOx EMISSIONS (Tg N yr-1) TO TROPOSPHERE STRATOSPHERE 0.2 LIGHTNING 5.8 FOSSIL FUEL 23.1 SOILS 5.1 BIOMASS BURNING 5.2 BIOFUEL 2.2 AIRCRAFT 0.5

15. OZONE POLLUTION IN THE UNITED STATES 90th percentiles of summer afternoon (1-5 pm) surface ozone concentrations (ppbv), 1980-1995 Fiore et al. [1998]