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

Transcription

1 HTAP, NASA JPL, 2/2/2012 Transport of Asian ozone pollution into surface air over the western U.S. in spring Meiyun Lin 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: /2011jd016961, in press. Geophysical Fluid Dynamics Laboratory

2 GFDL AM3 Sondes AQS/CASTNet Process-oriented analysis of multiplatform 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 variability in ozonesondes Jaegle et al., 2003; Liang et al., 2007; Jonson et al., 2010] [e.g. 3) Prior multi-model evaluations on campaign /monthly mean basis [e.g. Dentener et al 2006; Stevenson et al., 2006; Fiore et al., 2009] 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

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 (~50 km) 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 C48 (~200 km) U.S. (4-7 ppb) Large-scale conclusions independent of resolution High-res spatially refines estimates: 1-2 ppbv (~20%) higher over the highaltitude areas How good is the model?

4 The GFDL AM3 model explains 50-90% of observed daily O 3 variability in Point Reyes sonde CalNex sondes 6-9 km 3-6 km Cooper et al., 2011 Sonde AM3/C180 (~50 km) AM3/C48 (~200 km) All sites: 30-90% Source attribution? < 3 km 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 O 3 -strat Ozone (ppbv) Ozone (ppbv) Observed GFDL AM3 Zero Asian emissions O 3 -strat Improved stratospheric ozone tracer (O 3 -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 Observed GFDL AM3 Zero Asian emissions O 3 -strat Careful attribution of O 3 sources in continental inflow Necessitate a model representing dynamic variability of UT/LS O 3 and STE How much does Asian pollution contribute to surface high-o 3 events?

7 Asian pollution contribution to high surface O 3 events, confounding to attain tighter standard in WUS Obs (CASTNet/AQS) AM3/C180 total ozone AM3/C180 Asian ozone June June Max daily 8-h average Tighter standard harder to attain with domestic control

8 Transport of Asian pollution on the isentropic surfaces to the lower troposphere over the LA Basin Asian enhancements to trop column O 3 on May 8, 2010 Vertical cross-section of Asian O 3 along California coast [ppb] Previously identified isentropic transport mechanism [Brown- Steiner and Hess, 2011] θ [K] 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 O 3 in the ppb range over Southern California, Arizona 25th

10 Lessons learned: 1) Mixing of pollution and stratospheric air in continental inflow Necessitate models representing key features for accurate attribution 2) Asian emissions can contribute ~8-15 ppb to observed high-o 3 events Implications for attaining more stringent standards 3) Potential to forecast intercontinental O 3 transport events from space Require further work to be quantitative Ongoing work relevant for TF HTAP: 1) Stratospheric contribution to high surface O 3 events in WUS (Poster) 2) Historical variability, trends, and source attribution for Stratospheric exchange, fires, emissions, and climate (e.g. ENSO) Recommendations for TF HTAP: 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 Meiyun.Lin@noaa.gov

11 Extra slides

12 The new GFDL CM3/AM3 chemistry-climate model GFDL-AM3 GFDL-CM3 Donner et al., Golaz et al., Griffies et al., J. Climate, 2011 Modular SSTs/SIC Ocean from Model observations version 4 or (MOM4) CM3 CMIP5 Simulations & Sea Ice Model AM3 option to nudge to reanalysis winds Forcing Solar Radiation Well-mixed Greenhouse Gas Concentrations Volcanic Emissions Ozone Depleting Substances (ODS) Pollutant Emissions (anthropogenic, ships, biomass burning, natural, & aircraft) Naik et al., in prep Atmospheric Dynamics & Physics Radiation, Convection (includes wet deposition of tropospheric species), Clouds, Vertical diffusion, and Gravity wave Atmospheric Chemistry 86 km Chemistry of O x, HO y, NO y, Cly, Br y, and Polar Stratospheric Cloud (PSC) Chemistry of gaseous species (O 3, CO, NO x, hydrocarbons) and aerosols (sulfate, carbonaceous, mineral dust, sea salt, secondary organic) Aerosol-Cloud Interactions Dry Deposition 0 km Land Model version 3 (soil physics, canopy physics, vegetation dynamics, disturbance and land use) 48 vertical levels Surface 86 km AM3 cubed sphere grid C48 (~200x200 km 2 ) C180 (~50x50 km 2 ) M. Lin, et al., JGR, 2012 How good is the model?

13 Transpacific transport of Asian pollution: the view from satellite (10 18 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-today variability in Asian ozone pollution over WUS? Correlation of Asian ozone pollution enhancement at Grand Canyon NP in GFDL AM3 with AIRS CO columns, 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 O 3 at WUS National Parks peak 1-2 days after AIRS CO averaged over NE Pacific AIRS CO over NE Pacific (10 18 molec cm -2 ) AM3 Asian O 3 at 3 WUS sites (ppb) 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 O 3 -strat identical to O 3 in stratospheric air masses; subject to chemical and depositional loss in tropospheric air masses Transport of O 3 -strat and e90 both driven by meteorology