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Transport of Asian ozone pollution into surface air over the western U.S. in spring

Transport of Asian ozone pollution into surface air over the western U.S. in spring. Meiyun Lin. HTAP, NASA JPL, 2/2/2012.

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Transport of Asian ozone pollution into surface air over the western U.S. in spring

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  1. Transport of Asian ozone pollution into surface air over the western U.S. in spring Meiyun Lin HTAP, NASA JPL, 2/2/2012 Lin, M., A. M. Fiore, L. W. Horowitz, O. R. Cooper, V. Naik, J. S. Holloway, B. J. Johnson, A. M. Middlebrook, S. J. Oltmans, I. B. Pollack, T. B. Ryerson, J. Warner, C. Wiedinmyer, J. Wilson, and B. Wyman (2012), J. Geophys. Res., doi:10.1029/2011JD016961, in press.

  2. Process-oriented analysis of multi-platform observations with a new, global high-resolution chemistry-climate model Problems: 1) Coinciding ozone maxima of stratospheric and anthropogenic origin[e.g. Stohl and Trickl 1999; Cooper et al 2004; Ambrose et al., 2011] 2) Limitations of tropospheric CTMs in capturing observed dynamic variabilityin ozonesondes[e.g. Jaegle et al., 2003; Liang et al., 2007; Jonson et al., 2010] 3) Prior multi-model evaluations on campaign /monthly mean basis [e.g.Dentener et al 2006;Stevenson et al., 2006; Fiore et al., 2009] GFDL AM3 Our Approach: 1) Global high-res (50 km) with fully coupled strat+trop chemistry [Donner et al., 2011]; Nudged to GFS 2) Analyze transport events on daily basis, leveraging intensive measurements from CalNex 2010 Sondes AQS/CASTNet

  3. Mean Asian impacts on U.S. surface O3 in spring:high-resolution model spatially refines estimates Daily max 8-h average O3 in surface air, May-June 2010 average C180 (~50km) Diagnosed as difference between pairs of simulations: Base – Zero Asian anthrop. Emissions: Asian INTEX-B scaled to 2010, US NEI2005, ACCMIP elsewhere • Maximum in the western U.S. (4-7 ppb) • Large-scale conclusions independent of resolution • High-res spatially refines estimates: 1-2 ppbv (~20%) higher over the high-altitude areas C48 (~200km) How good is the model?

  4. The GFDL AM3 model explains 50-90% of observed daily O3variability in Point Reyes sonde CalNex sondes 6-9 km 3-6 km Cooper et al., 2011 Sonde < 3 km AM3/C180 (~50 km) AM3/C48 (~200 km) All sites: 30-90% • Source attribution? Lin, M et al., in prep, 2012

  5. Trans-Pacific transport of Asian pollution plumes to WUS often coincides with ozone injected from stratosphere 20-30% from Asia ~50% from O3-strat Ozone (ppbv) Ozone (ppbv) Zero Asian emissions O3-strat GFDL AM3 Observed Improved stratospheric ozone tracer (O3-strat), w/ tropopause diagnosed by the e90 tracer of Prather et al. [2010]

  6. Full chemistry AM3 captures the interleaving and mixing of Asian pollution and stratospheric air Primarily strat O3-strat GFDL AM3 Observed Zero Asian emissions • Careful attribution of O3 sources in continental inflow • Necessitate a model representing dynamic variability of UT/LS O3 and STE • How much does Asian pollution contribute to surface high-O3 events?

  7. Asian pollution contribution to high surface O3 events, confounding to attain tighter standard in WUS AM3/C180 total ozone Obs (CASTNet/AQS) AM3/C180 Asian ozone June 21 2010 June 22 2010 Max daily 8-h average Tighter standard… harder to attain with domestic control

  8. Transport of Asian pollution on the isentropic surfacesto the lower troposphere over the LA Basin Asian enhancements to trop column O3 on May 8, 2010 Vertical cross-section of Asian O3 along California coast [ppb] θ [K] Previously identified isentropic transport mechanism [Brown-Steiner and Hess, 2011] Asian ozone available to be intercepted by the elevated terrain or entrained into the daytime boundary layer (~1-4 km in depth)

  9. The Asian enhancement increases for total O3 in the 70-80 ppb range over Southern California, Arizona 25th

  10. Lessons learned: • Mixing of pollution and stratospheric air in continental inflow •  Necessitate models representing key features for accurate attribution • Asian emissions can contribute ~8-15 ppb to observed high-O3events •  Implications for attaining more stringent standards • 3) Potential to forecast intercontinental O3 transport events from space •  Require further work to be quantitative 1) Conduct process-oriented analysis of factors contributing to model differences 2)High-resolution model analysis of continental inflow processes 3) Evaluate models with high temporal frequency observations 4) A common emission inventory across models Ongoing work relevant for TF HTAP: • Stratospheric contribution to high surface O3 events in WUS (Poster) • Historical variability, trends, and source attribution for 1980-2010 • … Stratospheric exchange, fires, emissions, and climate (e.g. ENSO) Recommendations for TF HTAP: Meiyun.Lin@noaa.gov

  11. Extra slides

  12. The new GFDL CM3/AM3 chemistry-climate model Donner et al., Golaz et al.,Griffies et al., J. Climate, 2011 Modular Ocean Model version 4 (MOM4) & Sea Ice Model SSTs/SIC from observations or CM3 CMIP5 Simulations GFDL-AM3 GFDL-CM3 AM3 option to nudge to “reanalysis winds” Forcing Solar Radiation Well-mixed Greenhouse Gas Concentrations Volcanic Emissions Atmospheric Dynamics & Physics Radiation, Convection (includes wet deposition of tropospheric species), Clouds, Vertical diffusion, and Gravity wave 48 vertical levels Surface  86 km Atmospheric Chemistry 86 km 0 km Ozone–Depleting Substances (ODS) AM3 cubed sphere grid  C48 (~200x200 km2)  C180 (~50x50 km2) M. Lin, et al., JGR, 2012 Chemistry of Ox, HOy, NOy, Cly, Bry, and Polar Stratospheric Cloud (PSC) Chemistry of gaseous species (O3, CO, NOx, hydrocarbons) and aerosols (sulfate, carbonaceous, mineral dust, sea salt, secondary organic) Pollutant Emissions(anthropogenic, ships, biomass burning, natural, & aircraft) Aerosol-Cloud Interactions Dry Deposition • How good is the model? Land Model version 3 (soil physics, canopy physics, vegetation dynamics, disturbance and land use) Naik et al., in prep

  13. Transpacific transport of Asian pollution: the view from satellite (1018 molecules cm-2) AIRS retrievals of CO total columns (version 5.2 level 3 daily 1ºx1º gridded products, McMillan et al., 2011)

  14. Potential for developing space-based “indicators” for day-to-day variability in Asian ozone pollution over WUS? Correlation of Asian ozone pollution enhancement at Grand Canyon NP in GFDL AM3 with AIRS COcolumns, considering time lags of 1-3 days, May-June 2010 Grand Canyon NP  Advanced warning of Asian impacts on WUS surface O3? • Qualitatively promising… but short data set, need further testing r

  15. Asian enhancements to MDA8 O3 at WUS National Parks peak 1-2 days after AIRS CO averaged over NE Pacific AM3 Asian O3 at 3 WUS sites (ppb) AIRS CO over NE Pacific (1018 molec cm-2) • Qualitatively promising… but short data set • Need further test for a quantitative relationship and extending to other years?

  16. Stratospheric ozone tracer • Distinguish “stratospheric” vs. “tropospheric” air masses using the e90 tracer proposed by Prather et al. [2010]; allowing double tropopause • Set O3-strat identical to O3 in “stratospheric” air masses; subject to chemical and depositional loss in “tropospheric” air masses • Transport of O3-strat and e90 both driven by meteorology

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