WORKSHOP ON CLIMATE CHANGE AND AIR QUALITY : part I: Intercontinental transport and climatic effects of pollutants OBJECTIVE: Define a near-term (-2003) research strategy for EPA/OAQPS to 1.Better understand the role of intercontinental transport in affecting ozone and PM air quality; 2.Better understand the global/regional climate forcing of air pollutants (BC, OC, sulfate, ozone); 3.Enable an integrated appproach to assess the combined air quality and climatic implications of changes in anthropogenic emissions. Develop a longer-term program for integrating intercontinental transport and climatic forcing issues in EPA’s regulatory strategy

Dust transport over the Pacific, April 21-25, R. Husar

Asian Dust Cloud Over North America GOES Satellite Image PM10 West Coast R. Husar

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

SURFACE OZONE BACKGROUND PRODUCED OUTSIDE NORTH AMERICA 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.)

GLOBAL RADIATIVE FORCING OF CLIMATE, 1750-present IPCC [2001]

Aerosol Effect on Surface Reflectance Aerosols add to the reflectance and sometimes reduce the reflectance of surface objects Aerosols always diminish the contrast between dark a bright surface objects They change the color of surface objects Haze adds a bluish while dust adds yellowish tint to the surface color of surface objects.

Future SO 2 emissions in Asia are likely to be much lower than the latest IPCC forecasts

Indexed trends in greenhouse-gas emissions in China The net effect of these emission changes on global mean temperatures is an INCREASE, due to the dominant effect of the sulfate aerosol

M.Z. Jacobson

PRIORITY QUESTIONS AND STRATEGIES FOR PHASE II OF EPA/OAQPS INITIATIVE, How will changing anthropogenic emissions outside North America enhance background ozone and PM concentrations in the U.S., and the ability of the U.S. to meet the NAAQS? Need improved 2000 global, gridded emission inventories for ozone and PM precursors partitioned by source sector Need policy-relevant 2020 emission projections Need nested global  regional model Need to determine the PM background levels contributed by intercontinental transport 2.How will changes in emissions of PM, PM precursors, and ozone precursors, in the U.S. and in the rest of the world, contribute to climate change? Need GCM calculations of climate response for selected policy- relevant emission projections, develop approach for linearizing the dependence of climate response on the perturbation 3.How do U.S emissions affect the ability of countries in Europe and Asia to meet their air quality objectives?

GOING BEYOND 2003: SOME PRIORITY ISSUES –Link to air quality objectives outside North America through different nested model strategies –Use observations from satellites and aircraft field campaigns to Test model estimates of intercontinental transport Improve emission estimates (esp. fires, megacities) –Better define errors and error covariances in emission inventories towards improving these estimates through inversion models.

QUANTIFYING INTERCONTINENTAL TRANSPORT THROUGH INTEGRATION OF OBSERVATIONS AND MODELS 3-D CHEMICAL TRACER MODELS INTERCONTINENTAL TRANSPORT: CONCENTRATIONS, FLUXES, BUDGETS 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