FAM (Future Airborne Missions) Presentation: Tropospheric Ozone and Photochemistry

1. FAM (Future Airborne Missions) Presentation: Tropospheric Ozone and Photochemistry Anne Thompson, Bill Brune Virginia Beach, 8 March 07

2. Approach • Questions about ozone, photochemistry are formulated (6) • For each one: • Review expected ~2010 satellite observation • What sub-orbital observations are needed? • Which models and/or other information are needed?

3. 1. Tropospheric O3 • What are contributions to free O3 budget – stratosphere, lightning and/or convective-pollution mix, imported O3?

4. 1. Tropospheric O3 (Cont’d) • Expected 2010 satellite observations • Ozone from TES, OMI residuals, ACE, SCIAMACHY • Tracers - CO (MOPITT/AIRS/TES), NO2 (OMI) • Suborbital measurements adding value: • Assuming evolving validation & product refinement, in-situ O3 & tracer measurements from A/C, sondes, lidar to interpret O3 sources. • Coordinated tracers at appropriate frequency, duration, resolution. Lightning data, meteorology! • Trends from surface to UT/LS; maintain sondes in critical regions • New modeling capabilities – better forecasts assumed

5. 2. Oxidizing Capacity • Do we understand global atmospheric oxidation & its trends? • Left: Compare median OH vertical profiles – INTEX-NA: measured (circles), modeled (stars). Gray = all 1-min measurements of OH • Right: Measured-to-modeled OH ratios - INTEX-A (circles), TRACE-P (stars), PEM Tropics B (triangles). Individual INTEX-A 1-min measurements (gray dots).

6. 2. Oxidizing Capacity (Cont’d) Do we understand global atmospheric oxidation & its trends? Expected 2010 satellite observations Satellite O3, NO2, CO, lightning flashes (coarse vertical resolution?) Suborbital measurements adding value Complete A/C instrument suite in critical locations & conditions (eg, convection, UT/LS in midlatitudes) Trends, LT, MT, UT/LS, globally; continuity of existing networks (lifetime expt), focused expansion in critical regions New measurement & modeling capabilities Improved accuracy, intercomparisons, reliability of current instruments for NOx, NOy, HOx, RO2 as well as precursors & reactants Chemical-transport models - improved resolution, emissions

7. 3. Photochemistry (I) Is measured ozone production varying as expected with NOx? P(O3) = k {[HO2] + [RO2]}[NO] Figure shows NO with OH (upper pair) And HO2 (lower pair). Individual INTEX-A 1-min data shown (gray dots). Measured (circles), modeled (stars) Lower Panels: Measured-to-modeled ratios in INTEX-A (circles), TRACE-P (stars) and PEM Tropics B (triangles). All lines based on median profiles.

8. 3. Photochemistry (I, Cont’d) Is measured ozone production varying as expected with NOx? Expected 2010 satellite observations Satellite O3, NO2, CO, lightning flashes (coarse vertical resolution?) Suborbital measurements adding value Complete A/C measurements, including NO, HO2, RO2, in critical locations and conditions (eg polar regions with biomass burning, lightning over clean BL) New measurement & modeling capabilities Higher resolution models to test non-linear ozone production

9. 4. Photochemistry (II) Is the NOx budget known in all environments? Figure shows HO2 (observed to modeled) vs NO with INTEX-NA 1-min data. Other relevant data (NOy partitioning in Cohen & Atlas data, eg short-chain alkyl nitrates, oxygenated alkyl nitrates)

10. 4. Photochemistry (II, Cont’d) Is the NOx budget known in all major environments? Expected 2010 satellite observations • OMI NO2, TES OMI residual O3; OMI aerosol; MODIS dust/ particles Suborbital measurements adding value • Complete A/C suite; tracers to fingerprint NOx sources Need for new measurement & modeling capabilities • Laboratory measurements of homogeneous & heterogeneous nitrogen partitioning processes

11. 5. Photochemistry (III) Halogens: What role do they play in global oxidation chemistry? Expected 2010 satellite observations • TES & MOPPITT CO, TES O3, OMI NO2, BrO, HCHO, O3 • OMI aerosol; MODIS dust/ particles Suborbital measurements adding value • A/C measurement suite with all radicals, radical precursors, environmental parameters (photolysis frequencies, aerosol particle properties, …) Need for new measurement & modeling capabilities • A/C BrO with sub pptv precision • A/C Cl with pptv precision

12. 6. Photochemistry (IV) Is the formation of secondary organic aerosols understood? Expected 2010 satellite observations • OMI HCHO, O3products • OMI aerosol; MODIS dust/particles Suborbital measurements adding value • A/C and ground measurements of VOCs, oxidants, particle properties & evolution. Need for new measurement & modeling capabilities • Models need to be used extensively to bridge suborbital observations – satellite gap and for global extrapolation