Geophysical Fluid Dynamics Laboratory

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

Meiyun LinMeiyun 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:10.1029/2011JD016961, in press.

HTAP, NASA JPL, 2/2/2012

Process-oriented analysis of multi-Process-oriented analysis of multi-platform observations with a new, global platform observations with a new, global high-resolution chemistry-climate modelhigh-resolution chemistry-climate model

Sondes

AQS/CASTNet

GFDL AM3 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 [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]

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

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

Diagnosed as difference between pairs of simulations: Base – Zero Asian anthrop.

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

C48 (~200 km)

C180 (~50 km)

How good is the model?

Emissions: Asian INTEX-B scaled to 2010, US NEI2005, ACCMIP elsewhere

The GFDL AM3 model explains 50-90% of observed daily O3 variability in Point Reyes sonde

Cooper et al., 2011

Lin, M et al., in prep, 2012

CalNex sondes

All sites: 30-90%

SondeAM3/C180 (~50 km)AM3/C48 (~200 km)

< 3 km

3-6 km

6-9 km

Source attribution?

Trans-Pacific transport of Asian pollution plumes to WUS often coincides with ozone injected from stratosphere

Observed GFDL AM3 Zero Asian emissions O3-strat

~50% from O3-strat

20-30% from Asia

Ozone (ppbv) Ozone (ppbv)

Improved stratospheric ozone tracer (O3-strat), w/ tropopause diagnosed by the e90 tracer of Prather et al. [2010]

How much does Asian pollution contribute to surface high-O3 events?

Careful attribution of O3 sources in continental inflow Necessitate a model representing dynamic variability of UT/LS O3

and STE

Observed GFDL AM3 Zero Asian emissions O3-strat

Full chemistry AM3 captures the interleaving and mixing of Asian pollution and stratospheric air

Primarily strat

Obs (CASTNet/AQS) AM3/C180 total ozone AM3/C180 Asian ozone

Asian pollution contribution to high surface O3 events,confounding to attain tighter standard in WUS

June 212010

June 222010

Tighter standard… harder to attain with domestic control

Max daily 8-h average

Transport of Asian pollution on the isentropic surfacesto the lower troposphere over the LA Basin

Previously identified isentropic transport mechanism [Brown-Steiner and Hess, 2011]

Asian enhancements to trop column O3 on May 8, 2010

Vertical cross-section of Asian O3 along California coast

θ[K]

[ppb]

Asian ozone available to be intercepted by the elevated terrain or entrained into the daytime boundary layer (~1-4 km in depth)

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

25th

Lessons learned:

1) Conduct process-oriented analysis of factors contributing to model differences2) High-resolution model analysis of continental inflow processes 3) Evaluate models with high temporal frequency observations4) A common emission inventory across models

Recommendations for TF HTAP:

Ongoing work relevant for TF HTAP:

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-O3 events

Implications for attaining more stringent standards 3) Potential to forecast intercontinental O3 transport events from space Require further work to be quantitative

1) Stratospheric contribution to high surface O3 events in WUS (Poster)

2) Historical variability, trends, and source attribution for 1980-2010… Stratospheric exchange, fires, emissions, and climate (e.g. ENSO)

Meiyun.Lin@noaa.gov

Extra slides

The new GFDL CM3/AM3 chemistry-climate model

AM3 cubed sphere grid C48 (~200x200 km2) C180 (~50x50 km2)M. Lin, et al., JGR, 2012

Donner et al., Golaz et al., Griffies et al., J. Climate, 2011

Naik et al., in prep

48 vertical levels Surface 86 km

Atmospheric Chemistry 86 km

0 km

Atmospheric Chemistry 86 km

0 km

Atmospheric Dynamics & PhysicsRadiation, Convection (includes wet

deposition of tropospheric species), Clouds, Vertical diffusion, and Gravity wave

Atmospheric Dynamics & PhysicsRadiation, Convection (includes wet

deposition of tropospheric species), Clouds, Vertical diffusion, and Gravity wave

Chemistry of gaseous species (O3, CO, NOx, hydrocarbons) and aerosols

(sulfate, carbonaceous, mineral dust, sea salt, secondary organic)

Dry Deposition

Aerosol-Cloud Interactions

Chemistry of Ox, HOy, NOy, Cly, Bry, and Polar Stratospheric Cloud (PSC)

ForcingSolar Radiation

Well-mixed Greenhouse Gas ConcentrationsVolcanic Emissions

ForcingSolar Radiation

Well-mixed Greenhouse Gas ConcentrationsVolcanic Emissions

Ozone–Depleting Substances (ODS)

Ozone–Depleting Substances (ODS)

Modular Ocean Model version 4 (MOM4)&

Sea Ice Model

Modular Ocean Model version 4 (MOM4)&

Sea Ice Model

Pollutant Emissions (anthropogenic, ships,

biomass burning, natural, & aircraft)

Pollutant Emissions (anthropogenic, ships,

biomass burning, natural, & aircraft)

Land Model version 3(soil physics, canopy physics, vegetation

dynamics, disturbance and land use)

Land Model version 3(soil physics, canopy physics, vegetation

dynamics, disturbance and land use)

SSTs/SIC from observations or CM3 CMIP5 Simulations

SSTs/SIC from observations or CM3 CMIP5 Simulations

GFDL-CM3GFDL-CM3GFDL-AM3GFDL-AM3 AM3 option to nudge to “reanalysis winds”

How good is the model?

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)

Potential for developing space-based “indicators” for day-to-day variability in Asian ozone pollution over WUS?

r

Advanced warning of Asian impacts on WUS surface O3?

Qualitatively promising… but short data set, need further testing

Grand Canyon NP

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

Asian enhancements to MDA8 O3 at WUS National Parks peak 1-2 days after AIRS CO averaged over NE Pacific

Qualitatively promising… but short data setNeed further test for a quantitative relationship and extending to

other years?

AIR

S C

O o

ver

NE

Pac

ific

(10

18 m

ole

c cm

-2)

AM

3 A

sian

O3

at 3

WU

S s

ites

(p

pb

)

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

Stratospheric ozone tracer