CONTINENTAL OUTFLOW AND INTERCONTINENTAL TRANSPORT AT NORTHERN MIDLATITUDES (and a few UT/LS topics) Daniel J. Jacob Atmospheric Chemistry Modeling Group Harvard University

ARE ATMOSPHERIC OBSERVATIONS OF ACETONE CONSISTENT WITH CURRENT UNDERSTANDING OF SOURCES AND SINKS? TRACE-A SONEX ABLE -3B PEM -WB PEM-TB Surface sites

GLOBAL BUDGET OF ATMOSPHERIC ACETONE Singh et al. Jacob et al. [2002] [2000] (a priori) (a posteriori) SOURCES (Tg yr -1 ) 56 (37-80) 78 (49-105) 95 (80-110) Terrestrial vegetation 15 (10-20) 26 (0-52) 33 (24-42) Plant decay 6 (4-8) 9 (0-18) 2 (-3-7) Biomass burning 5 (3-10) 3 (2-5) 5 (3-7) Industry 2 (1-3) 1 (1-2) 1 (1-2) Oceans 0 10 (0-20) 27 (21-33) Oxidation of isoalkanes 17 (12-24) 20 (10-30) 21 (16-26) Oxidation of terpenes, MBO 11 (7-15) 9 (3-15) 7 (3-11) SINKS (Tg yr-1) 56 (37-80) Photolysis 36 (24-51) Oxidation by OH 13 (9-19) Deposition to land 7 (4-10) 9 9 Uptake by ocean LIFETIME 16 days 20 days 15 days

OCEANIC SIGNATURE IN ATMOSPHERIC ACETONE OBSERVATIONS Low winter values over Europe imply ocean sink southern Norway [Solberg et al., 1996] High values over South Pacific imply large ocean source South Pacific [Singh et al., 2001] a priori sources/sinks;  2 = 1.3 a posteriori sources/sinks (including “microbial” ocean sink, photochemical ocean source);  2 = 0.39

SURFACE AIR ACETONE CONCENTRATIONS IN A POSTERIORI SIMULATION

METHYL IODIDE: TRACER OF MARINE CONVECTION IN GLOBAL ATMOSPHERIC MODELS Loss by photolysis (~4 days), relatively uniform ocean source, large aircraft data base [D.R. Blake, UCI] Simple model for ocean source Observations Model (GEOS-CHEM) Define Marine Convection Index (MCI) as ratio of upper tropospheric (8-12 km) to lower tropospheric (0-2.5 km) CH 3 I concentrations MCI over Pacific ranges from 0.11 (Easter Island dry season) to 0.40 (observations over tropical Pacific GEOS-CHEM reproduces observed MCI with little global bias (+11%) but poor correlation (r 2 = 0.15, n=11) Bell et al. [2002] MCI: 0.40 (obs) 0.22 (mod) MCI: 0.16 (obs) 0.14 (mod)

SURFACE OZONE BACKGROUND IN THE U.S. IMPORTED FROM OUTSIDE 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.)

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. [2002]

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 U.S. OZONE STANDARD WERE TO DECREASE! Fiore et al. [2002] tropical air Subsidence of Asian pollution + local production stagnation U.S. standard European standards

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

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. [2002]

FORECASTING TRANSATLANTIC TRANSPORT OF NORTH AMERICAN POLLUTION TO EUROPE WITH 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. [2002] Greenhouse warming  NAO index shift  change in transatlantic transport of pollution

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. [2002]

Enhancements in Asian surface ozone due to European anthropogenic emissions (GEOS-CHEM, 1996) Liu et al. [2002]

GLOBAL MODEL ANALYSIS OF OZONESONDE OBSERVATIONS ALONG THE PACIFIC RIM ( ) observations GEOS-CHEM model High UT variability at Hong Kong in winter-spring reflects alternance of tropical and stratospheric influences Liu et al. [2002] Spring enhancement from SE Asian biomass burning Hong Kong, hPa hPa hPa

ALTERNANCE OF TROPICAL AND STRATOSPHERIC INFLUENCES IN WINTER UT OVER HONG KONG: comparison of Dec 24, 1996 and Jan 6, 1997 Observed GEOS-CHEM Sonde and model profiles Model ozone concentrations and fluxes, 200 hPa Stratospheric ozone tracer at longitude of Hong Kong Liu et al. [2002]

200 hPa ozone fluxes across Pacific Rim (GEOS-CHEM, 1996) Tropical and midlatitude influences Easterly circulation away from Pacific in summer Liu et al. [2002]

SUMMER UT OZONE POLLUTION EVENT OVER HONG KONG August 21, 1996 Observed GEOS-CHEM Asian pollution Sonde and model profiles Model enhancement of ozone concentrations and fluxes due to Asian anthropogenic sources Liu et al. [2002]

WHAT OBSERVATIONS AND MODELS ARE NEEDED TO BETTER QUANTIFY INTERCONTINENTAL TRANSPORT? 3-D CHEMICAL TRACER MODELS INTERCONTINENTAL TRANSPORT: CONCENTRATIONS AND FLUXES SATELLITE OBSERVATIONS Global and continuous but few species, low resolution AIRCRAFT OBSERVATIONS High resolution, targeted flights provide critical snapshots for model testing SURFACE OBSERVATIONS high resolution but spatially limited Source/sink inventories Assimilated meteorological data Chemical and aerosol processes

TRACE-P MISSION (Mar-Apr 2001) Emissions -Fossil fuel -Biomass burning -Biosphere, dust Long-range transport from Europe, N. America, Africa ASIA PACIFIC P-3 Satellite data in near-real time: MOPITT TOMS SEAWIFS AVHRR LIS DC-8 3D chemical model forecasts: - ECHAM - GEOS-CHEM - Iowa/Kyushu - Meso-NH -LaRC/U. Wisconsin FLIGHT PLANNING Boundary layer chemical/aerosol processing ASIAN OUTFLOW Stratospheric intrusions PACIFIC

GOME daily data of NO 2 and HCHO tropospheric columns during TRACE-P (3/15 - ) Randall Martin Mean slant NO 2 column, 3/16-4/15 Slant HCHO column, single orbit on 3/27 Thomas Kurosu/Kelly Chance

CARBON MONOXIDE CONCENTRATIONS MEASURED IN TRACE-P

Don Blake, UCI Symbol size  1/altitude C 2 Cl 4 CONCENTRATIONS MEASURED IN TRACE-P

INVERSE ANALYSIS OF CO SET UP FOR TRACE-P a priori Asian emissions appear low but not outrageously so Paul Palmer, Harvard

PRELIMINARY GLOBAL (GEOS-CHEM) 3-D MODEL ANALYSIS OF TRACE-P OBSERVATIONS Mat Evans, Harvard

GLOBAL MODEL ANALYSIS OF TRACE-P OBSERVATIONS: SENSITIVITY TO SOURCES Mat Evans, Harvard Median model/observed OZONECO Median model/observed

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 The next NASA Global Tropospheric Experiment (GTE) mission

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

INTEX-NA HAS LINKAGES WITH A NUMBER OF ATMOSPHERIC PROGRAMS In situ –North American Carbon Program (2002-) –NOAA Northeast U.S. Study (2004) –European UT/LS program (-2005) - LET’S TALK!!! –Asian APARE program (ongoing) Satellites –Terra [MOPITT] (1999-) –Envisat [SCIAMACHY, MIPAS] (2002-) –NMP/GIFTS (2004-) –Aura [TES, OMI, HRDLS, TES] (2004-) Modeling –EPA OAQPS/ORD climate change/air quality initiative ( )