Climate Change. Air Quality. Stratospheric. Ozone. NAS study on International Transport of Air Pollution NOAA Perspective

Transcription

1 Climate Change Air Quality Stratospheric Ozone NAS study on International Transport of Air Pollution NOAA Perspective A.R. Ravishankara NOAA Climate Research and Modeling Program David Parrish NOAA/ESRL/Chemical Sciences Division

2 Climate Change Air Quality Stratospheric Ozone NAS study on International Transport of Air Pollution NOAA Perspective Why is NOAA interested in Long- Range Pollutant Transport? 3 areas of research and interest 2 are particularly tightly coupled

3 Climate Change Air Quality Atmospheric Composition: Importance of Lifetime Long-Lived gases are well-mixed and do not vary rapidly in time (globally). Short-Lived species are not well mixed; they are highly variable in space and time. Ozone and most of aerosols have added complexity they are made in the atmosphere. TIME SCALE 1s 100s 1hr 1 day 1yr 10 yrs 100 yrs Micro Scale Very Short- Lived Species CH 3 O 2 HO 2 Urban or Local Scale Short-Lived Species SO2 H 2 O 2 NO x DMS C 3 H 6 C 5 H 8 Regional or Mesoscale CO Aerosols Trop O 3 Synoptic or Global Scale Long-Lived CFC s Species N 2 O CH 4 CH 3 CCl 3 CH 3 Br NO 3 OH ,000 SPATIAL SCALE, km Inter -Hemispheric Mixing Time Concentrations of shorter-lived gases and aerosols need to be calculated. All concentrations have to be calculated for predictions! Intra -Hemispheric Mixing Time Boundary Layer Mixing Time

4 Climate Change Air Quality Convergence of Scales Global Spatial Scale of Decision Support Needs Climate Continental Forcing NOAA Regional Collaborations Regional Local Urban Air Quality Point Sources 70 s Time 2008

5 An Integrated Approach to Climate and Air Quality Supporting Regional and National Decision Making The focus of the climate change debate in the US is moving from Detection & Attribution to Management and Mitigation The Nation needs an integrated approach to management because The sources are the same - power plants, cars, industry, etc. The atmospheric processes that link sources to impacts are almost the same Increased efficiencies, additional benefits Several national and international studies and existing and proposed legislation call for an integrated approach Decision Matrix Maximize societal benefits from policies and management strategies designed to limit the emissions of man-made pollutants to the atmosphere. Seek win-win strategies. Minimize the overall cost of environmental regulation through integrated multi-issue approach to emissions management. Avoid win-lose strategies.

6 Climate Change Climate Forcing (RF) by non-co 2 Forcing Agents and Feedbacks Tropospheric and Stratospheric O 3 Aerosols Globally averaged top of radiative atmosphere forcing shown Local forcing highly variable - at the surface - in the atmosphere - large variation in space and time Much of variability and uncertainty comes from ozone and aerosols Involved in feedbacks (snow albedo, cloud albedo effects) Understanding long-range transport of O 3, aerosols and their precursors is critical to understanding variability, feedbacks and reducing the uncertainties.

7 Air Quality Imported Background O 3 Becoming More Important 8-hour Ozone Standard Has Been Lowered to 75 ppbv Nonattainment Areas in the U.S. Old 8-Hour Ozone Standard Estimated Future Nonattainment Areas Changing Standards Nonattainment Areas (347 Counties) 75 ppb Counties 70 ppb Counties 60 ppb Counties A.S.L. & Associates Understanding long-range transport of O 3 and its precursors is critical to understanding background O 3 concentrations.

8 Air Quality Imported Background O3 Becoming More Important, Background Ozone Concentrations are Increasing Parrish et al., 2008 Understanding long-range transport of O3 and its precursors is critical to understanding background O3 concentrations.

9 Air Quality Imported Background O 3 Becoming More Important, and Boundary Conditions are Required for Ozone Forecasts. NOAA Is Responsible for Operational AQ forecasts Question: Can forecasts be improved by incorporating dynamic boundary condition calculations? Understanding long-range transport of O 3 and its precursors is critical to understanding background O 3 concentrations.

10 Air Quality Asian Dust & Pollution Intermittent Aerosol Transport : Challenge for Air Quality Forecasting Alaskan & Canadian Forest Fires Wildfires Wind Blown Dust Smoke & Pollution African Dust Understanding long-range transport of aerosols and their precursors is critical to understanding PM air quality

11 Air Quality Other Issues: Relatively new concerns: Toxics: Local sources versus long-range transport Mercury POPs Combined AQ and Climate issues: How will climate change affect transport patterns? How will climate change affect source strengths (dust, wild fires)? How will climate change affect transformation processes during long-range transport?

12 Stratospheric Ozone Transport of anthropogenic emissions can potentially affect stratospheric O 3 Some Short-Lived species can affect chemistry of the stratosphere if transported there. Ozone precursors and aerosol surface are issues: VOC, SO 2, etc. TIME SCALE 1s 100s 1hr 1 day 1yr 10 yrs 100 yrs Micro Scale Very Short- Lived Species CH 3 O 2 HO 2 NO 3 Urban or Local Scale Short-Lived Species SO2 H 2 O 2 NO x DMS C 3 H 6 C 5 H 8 Regional or Mesoscale CO Aerosols Trop O 3 Synoptic or Global Scale Long-Lived CFC s Species N 2 O CH 4 CH 3 CCl 3 CH 3 Br Inter -Hemispheric Mixing Time Intra -Hemispheric Mixing Time Boundary Layer Mixing Time OH ,000 SPATIAL SCALE, km Long-range transport has a role even in our understanding of stratospheric O 3 concentrations.

13 Stratospheric Ozone Transport of anthropogenic emissions can potentially affect stratospheric O 3 Some Short-Lived species can affect chemistry of the stratosphere if transported there. Ozone precursors and aerosol surface are issues: VOC, SO 2, etc. Long-range transport has a role even in our understanding of stratospheric O 3 concentrations.

14 Stratospheric Ozone Transport of anthropogenic emissions can potentially affect stratospheric O 3 NASA DC-8 INTEX-A flights altitude (km) HC Data: D. Blake Analysis: M. Trainer Propane (pptv) Long-range transport has a role even in our understanding of stratospheric O 3 concentrations.

15 Climate Change Air Quality Stratospheric Ozone NAS study on International Transport of Air Pollution NOAA Perspective Thank you for your attention!