1. BRIDGING THE SCALES IN ATMOSPHERIC CHEMISTRY: LOCAL TO GLOBAL Daniel J. Jacob with Jenny A. Fisher, Monika Kopacz, Lin Zhang, Tzung-May Fu, Easan E. Drury, Eric M. Leibensperger, Shiliang Wu, Loretta J. Mickley, Chris D. Holmes and support from NASA, EPRI, NSF, EPA

2. SCALES OF ATMOSPHERIC CHEMISTRY PROBLEMS LOCAL < 100 km REGIONAL 100-1000 km GLOBAL > 1000 km Urban smog Point source Disasters Visibility Regional smog Acid rain Ozone layer Climate Biogeochemical cycles Annecy

3. SCALE SEPARATION AND INTERACTIONS BL turbulence, sea breezes… mesoscalesynoptic scale Deep convection subsidence LOCAL REGIONAL planetary waves, general circulation… GLOBAL OCEANS LAND  chem ~ 0.1-10 d  chem > 10 d fronts, monsoons…  chem < 1 d Non-linear chemical & aerosol evolution Dynamic/interactive boundary conditions

4. NASA/ARCTAS AIRCRAFT CAMPAIGN (April+July 2008) Objective: better understand changes in Arctic pollution and climate Fairbanks Cold Lake Yellowknife Aura Calipso Aqua A-train Focus on mid-latitudes pollution, Arctic haze (spring), boreal forest fires (summer) Asia N. America Fire plumes Mid-latitudesArctic Deposition Air quality Arctic climate forcing Europe

5. INTEGRATING SATELLITE, AIRCRAFT, AND MODEL INFORMATION TO BETTER UNDERSTAND SOURCES OF ARCTIC POLLUTION J.A. Fisher [Harvard], G. Diskin [LaRC], J. Warner [UMBC] Asian plume transported to Arctic in warm conveyor belt on April 16, 2008 Aircraft GEOS-Chem AIRSGEOS-Chem Aircraft CO data at 4-6 km (500 hPa) compared to GEOS-Chem chemical transport model AIRS satellite data for CO at 500 hPa compared to GEOS-Chem with averaging kernels Satellites provide global continuous observations; Aircraft provide satellite validation, complementary species, local process information; Models provide link between aircraft and satellite, platform for understanding and prediction

6. SATELLITES AND MODELS ARE INSEPARABLE 336-356 nm backscattered radiance spectrum measured from space Formaldehyde column Concentrations (OMI, JJA 2006) Isoprene emission fluxes Radiative transfer model & its inverse Chemical transport model & its inverse …must be viewed with in situ data as a unified observing system Millet et al. [JGR 2008] a priori info relationships to processes evaluation aircraft Surface sites Formaldehyde absorption lines

7. Aircraft: Aerosol chemistry Size distribution Optical properties INTEGRATING SATELLITE, AIRCRAFT, AND GROUND-BASED AEROSOL DATA TO CONSTRAIN U.S. AEROSOL SOURCES DURING ICARTT (Jul-Aug ’04) surface networks: IMPROVE (aerosol chemistry), AERONET (AOD) MODIS TOA reflectance GEOS-Chem chemical transport model MODIS c5 operational.product Synthetic top-of-atmosphere (TOA) reflectance backscattered radiation Optimize retrieval of aerosol optical depth (AOD) and surface concentrations GEOS-Chem AODs AERONET in circles MODIS AODs at 0.47  m Observed Model Sulfate OC dust 0.1 1  m Size distribution Difference between MODIS and GEOS-Chem AODs; constraint on aerosol sources Drury et al. (in prep.) prior info

8. INTEX-B AIRCRAFT CAMPAIGN OVER NORTHEAST PACIFIC (2006) CO columns TESGEOS-ChemAIRS Zhang et al. [ACP, in press] aircraft track A B AIRS and TES satellite observations of transpacific plume TES observes ozone as well as CO; observed ozone-correlation indicates ozone production over Pacific but signal is noisy (observations are sparse)

9. TRANSPACIFIC PLUME OBSERVED BY INTEX-B AIRCRAFT (May 9, 2006) B-south branch HNO 3 NO O3O3 CO Solid: observations Dash: GEOS-Chem A-north branch PAN CO O3O3 PAN Backward (7 d) and forward (3 d) trajectories for points A and B Ozone is produced in the southern branch following subsidence and decomposition of PAN to NO x Most of this ozone circles around the Pacific High and eventually dies during transport to western equatorial Pacific; only a small fraction reaches the western U.S. A B graveyard of Asian pollution Zhang et al. [ACP, in press]

10. CONSEQUENCES FOR U.S. SURFACE OZONE GEOS-Chem Asian pollution:9 ± 2 Observed: 54 ± 10 GEOS-Chem: 53 ± 8 U.S. surface ozone during INTEX-B campaign (April-May 2006) Observations (Dan Jaffe, UW) and GEOS-Chem at Mt. Batchelor, Oregon (2,700 m) 2000-2006 doubling of Asian NO x emissions has increased U.S. surface ozone by 1-3 ppbv in the West Zhang et al., ACP, in press Mean Asian surface pollution enhancement (GEOS-Chem) Apr 17 Apr 23 Apr 29 May 5 May 11 ppb

11. INTERCONTINENTAL SOURCE ATTRIBUTION OF OZONE USING MODEL ADJOINTS GEOS-Chem adjoint simulation for INTEX- B period (Apr-May 2006) Contribution of ozone production regions to ozone concentration at Mt. Batchelor Observatory 23% 21% 17% 6% Mean East Asian pollution enhancement of 9.2 ppb at MBO includes 5.6 ppb from China and 3.6 ppb from Japan+Korea Zhang et al. [in prep.]

12. ORIGIN OF HIGH ORGANIC AEROSOL CONCENTRATIONS IN FREE TROPOSPHERE? ACE-Asia aircraft data over Japan (April-May 2001) Observed (Huebert) GEOS-Chem model Observed (Russell) Heald et al. [GRL 2005] Observations show 1-3  g m-3 background; model including standard scheme for secondary organic aerosol (SOA) is too low by factor 10-100

13. ICARTT AIRCRAFT DATA OVER EASTERN U.S. (Jul-Aug 2004) Mean vertical profile of water-soluble organic carbon (WSOC) aerosol Observed (Weber) Model w/ dicarbonyl SOA added Model w/ standard SOA Correlation with other variables measured from aircraft (grey = obs, colors = model) Fu et al. [AE, submitted] includes SOA from irreversible cloud uptake of glyoxal & methylglyoxal

14. SENSITIVITY OF SURFACE AIR QUALITY TO METEOROLOGICAL VARIABLES Insights into the effect of climate change on air quality Ozone PM (aerosol) Stagnation Temperature Mixing depth Precipitation Cloud cover Humidity Effect of climate change = = ? ? = ? ? (relative) Jacob and Winner, AE 2008

15. IMPORTANCE OF MID-LATITUDES CYCLONES IN AIR POLLUTION METEOROLOGY Clean air sweeps behind cold front Cold fronts from mid-latitude cyclones are the principal ventilation process for U.S. Midwest/Northeast, western Europe, China IPCC shows decrease + N shift of cyclones from 21 st -century climate change; already seen in 1950-2000 climatological data

16. CORRELATIONS AND TRENDS OF POLLUTION EPISODES AND CYCLONES IN NORTHEAST U.S. # pollution episode days (O 3 >80 ppb) and # cyclones tracking across SE Canada in summer 1980-2006 observations Cyclone track Strong correlation; cyclone frequency is predictor of pollution episode frequency 1980-2006 decrease in cyclone frequency would imply a corresponding degradation of air quality if emissions had remained constant Expected # of 80 ppb exceedance days in Northeast dropped from 30 in 1980 to 10 in 2006, but would have dropped to zero by 2001 in absence of cyclone trend! Leibensperger et al. [ACP, submittted] # cyclones # episodes

17. ENSEMBLE MODEL ANALYSIS OF CLIMATE CHANGE EFFECT ON OZONE AIR QUALITY IN THE U.S. Northeast Midwest California Texas Southeast Models show consistent projection of ozone increase in Northeast/Midwest - likely reflects decrease in mid-latitude cyclone frequency …but large disagreements in Southeast - due in part to isoprene chemistry isoprene NO x isoprene nitrates ???? How will isoprene emissions actually respond to climate change? Increase in CO 2, land cover change… Weaver et al. [BAMS, submitted] Results from six coupled GCM-CTM simulations 2000-2050 change of 8-h daily max ozone in summer, keeping anthropogenic emissions constant ppb

18. REGIONAL CLIMATE SENSITIVITY TO ANTHROPOGENIC AEROSOLS Aerosol optical depths, at 550 nm  DJF surface temperatures 15-year GISS GCM simulation with zeroed U.S. aerosols vs. control present-day simulation Large warming over eastern U.S. (>1 o C), cooling in Arctic; teleconnection over East Asia Mickley et al. [in prep.] Sulfur emission controls will enhance warming – but by how much?

19. Atmospheric component of cycle: Hg(0) Hg(II) OH, O 3, Br aq, h deposition dry wet dry GLOBAL BIOGEOCHEMICAL CYCLING OF MERCURY ? ? ? ? ? PRESENT-DAY Inventories in Mg Flows in Mg a -1 5600 1,150,000 7000 Selin et al. [GBC 2008]

20. DIURNAL CYCLE OF REACTIVE GASEOUS MERCURY (RGM) IN MARINE BOUNDARY LAYER Early a.m. rise, midday peak suggests Br chemistry, deposition via sea salt uptake Hg(0) HgBr Br T Br, OH HgBrX sea-salt aerosol HgCl 3 2-, HgCl 4 2- deposition MBL budgets Model predicts that ~80% of Hg(II) in MBL should be in sea salt: Holmes et al. [in prep.] Observed [Laurier et al., 2003] Model Hg(0)+Br Model Hg(0)+OH Subtropical Pacific cruise data

21. SATELLITES:LEO, Geo, L1 orbits, lunar OBSERVING SYSTEM FOR ATMOSPHERIC COMPOSITION IN 2025 SURFACE SITES, SHIPS Long-term trends Surface fluxes Process information ROBOTIC AIRCRAFT Process information Surface fluxes Global/regional continuous mapping Top-down constraints on emissions Stratospheric monitoring Sun-Earth interactions ADAPTIVE EARTH SYSTEM MODELS Data assimilation, inversion Understanding & prediction