(Impacts are Felt on Scales from Local to Global)

1. Aerosols Link Climate, Air Quality, and Health:Dirtier Air and a Dimmer Sun (Impacts are Felt on Scales from Local to Global) Emissions == Impacts

2. Lifecycle of Particles in the Atmosphere • Some particles are emitted directly (e.g., dust, black carbon), while others are formed as result of atmospheric chemistry (sulfate) • Some emissions are due to natural process (e.g., sea salt), others due to anthropogenic activities (e.g., black carbon from coal combustion).

3. Models Play a Critical Role in Linking Emissions to Aerosol Distributions and Subsequent Effects Aerosols and climate and air quality share: common emissions; common models; and synergistic control/policy strategies Modeled Observed

4. Predicting Aerosol Distributions Have Added Complexities Of Emissions And Chemistry, And Size And Composition Matter! Maldives South Asia Aerosol Composition Size: SSA Sub-micron Super Data: ABC Project

5. Linking Emissions to Aerosol Distributions and Subsequent Effects • How good are the models? • What is the consistency of model-derived information? How model dependent are the results? • How uncertain are the model predictions? • What do the observations tell us about the quality of the calculation?

6. The Emission Estimates for Particles are Represent the Largest Source Of Uncertain % Uncertainty in Emissions BC 5.8 Tg/yr ~25% biofuels Energy-related 3.2 Tg/yr Important – the lifetime of aerosols in the atmosphere is on the order of days, while that for CO2 is many decades Open Burning

7. Model Intercomparison Studies Provide Valuable Information on Diversity of Model-Derived InformationDoes low diversity reflect scientific understanding or simply consensus? Comparison of 16 Global Aerosol Models Textor et al., ACP, Atmos. Chem. Phys. Discuss., 5, 8331–8420, 2005

8. Despite High Uncertainty Current Models Have Significant Predictive Capabilities Predicted Surface Black Carbon Concentrations Black carbon at the Maldives Observed Modeled Data: ABC Project

9. Linking Aerosol Distributions to Radiative Effects Adding Observational Constraints Reduces Uncertainty Dust Nss Sulfate Organics Sea Salt Black Carbon

10. The Effect On Calculated AOD When Using Observational Parameterizations For Optical Properties Can Be Large Observations based on field experiments (in situ data) A priori Constrained Bates et al., ACPD, 2006

11. Combining Satellite with Models Provides Improved Fields for Analysis Apriori AOD Model Prediction How to optimally adjust individual aerosol quantities given AOD (sulfate, BC, OC, dust, sea salt)? - AOD by itself not unique - Fine mode fraction helps – allows sulfate, black carbon and organic carbon to be modified separately from dust and sea salt AOD ADJUSTED MODEL AOD MODIS+AERONET Fine-fraction Total

12. Combining Satellite and Surface Measurements with Models Provides Improved Fields for Analysis How to optimally adjust individual aerosol quantities given AOD (sulfate, BC, OC, dust, sea salt)? - AOD by itself not unique - Fine mode fraction helps – allows sulfate, black carbon and organic carbon to be modified separately from dust and sea salt - SSA gives info to adjust absorption vs scattering – adjust black carbon separately from sulfate and organic carbon Maldives AOD MODIS+AERONET We need more surface observations! (for validation) Fine-fraction Total

13. Reductions Of Uncertainties When Measurements Are Used To Inform The Models Normalized uncertainties (uncertainty range of the indicated quantity divided by the value of the quantity) DRE: Direct radiative effect (all aerosols) DCF: Direct climate forcing (that portion due to anthropogenic aerosols) Bates et al., ACPD, 2006

14. Where do we go from here? Changes in China Emissions from 2001-2006 Due to Energy Growth and Improved Methodology SO2:  +44% NOx:  +65% CO:  +57% VOC: +51% BC:  +92% OC:  +17%

15. Development indicated by red and blue Guangzhou Another Twist to the Intercontinental Pollution Issue Hong Kong 2003 1993 50% higher than if done in the West !! Streets et al., ES&T, 2006

16. Emissions Due To Exports Have Significant Local Health/Climate Impacts AND They Contribute To Impacts in North America As Well! (Emissions due to exports in PRD can be offset at an annual cost of $250 million, or 0.3% of total exports value) MODIS AOD Asia Contribution Asia Contribution Heald et al., JGR, doi:10.1029/2005JD006847, 2006

17. Linking Emissions to Aerosol Distributions and Subsequent Effects -- Summary • Models play an essential role. • Models have improved substantially. • Further improvements will require reductions in key uncertainties (e.g., emissions, better basic understanding of some processes). • Closer integration of observations. • Air quality and climate linkage offerssynergistic policy/actions.

18. In the LMD-Z model, the change in net outgoing shortwave radiation in going from experiment 3 to experiment 4 is somewhat larger (−0.47Wm−2) than it is in going from experiment 4 to experiment 5 (−0.29Wm−2) but the change between experiment 4 and experiment 5 is still significant relative to the other changes introduced in these experiments. These changes are caused by large changes in the change in droplet concentrations (Fig. 3b) between the present day and pre-industrial simulations for experiment 5 compared to experiment 4, which are simply due to the large changes in present day and pre-industrial aerosols calculated by each of the models. Thus, within any one model, the change in net outgoing shortwave radiation is most sensitive to the calculation of individual aerosol fields than to anyof the other parameters in the cloud scheme.