Observation and Modeling Evidence of Ozone Transport to and from Asia

Hajime Akimoto(Oliver Wild and Pakpong Pochanart)

Frontier Research Center for Global Change (FRCGC)

Japan Agency for Marine-Earth Science and Technology (JAMSTEC)

LRTAP/EMEP Task Force on Hemispheric Transport of Air Pollutants, Brussels, June 1-3, 2005

Free Troposphere

Boundary Layer

N. America AsiaEurope

Intercontinental Transport at Northern Mid-latitudes

HH

H

LL L

Trans-Eurasian Transport

Motivations

• Trans-Pacific and Trans-Atlantic transport well studied

– PEM-West, TRACE-P, ACE-Asia, NARE, ITCT

• Trans-Eurasian transport less well understood

• Unique features

– meteorological mechanisms for export

– chemical influences due to latitude and meteorology

– emissions and deposition over continent

Questions

• How does pollutant export differ from that from N. America or East Asia? What are the impacts on oxidation and climate?

• To what extent does European pollution affect central and eastern Asia? How does this compare with N. American influence?

10% Increase of Emission in N. America

10% Increase of Emission in Europe

10% Increase of Emission in E. Asia

Model-calculated Characteristic of Intercontinental Transport from Three Continents

Adapted from: O. Wild, H. Akimoto, J. Geophys. Res., 106, 27,729 (2001)

longitude

Height

longitude longitude

O3 and CO over Eurasia

Mace HeadZugspitze

MondyHappo

Export of Oxidants from Europe

• Horizontal transport in PBL dominates export

• Seasonal variation in export dependent on species

Can European Pollution Affect East Asia?

Source: Newell and Evans [2000]

Trajectories Arriving at 100°E

Newell and Evans [2000]

European Impacts at 100°E

CO: greatest in high-latitude PBL in wintertime

O3: greatest in low/mid-trop in spring

close to zero in winter PBL

Remote Stations for Surface O3 from Europe to East Asia Mountain (1600-2000 m): Arosa, Mondy and Happo

Sea Level: Mace Head, Oki, and Okinawa

Arosa, Switzerland

Mondy, Russia

Happo, Japan

Seasonal Variation of Background Ozone in East Asia and Europe -Observation-

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

10

20

30

40

50

60

70

East Asia-EuropeSummer Minimum

Spring Maximum Mondy Background 1996-1999 Happo Background 1996-1997 Arosa Background 1996-1997 Mace Head Background

Ozone (ppb)

Month

Seasonal Variation of Regionally Polluted Ozone in East Asia and Europe -Observation-

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

10

20

30

40

50

60

70

Arosa Regionally Polluted 1996-1997 Happo Regionally Polluted 1996-1997

Happo - Arosa

Ozone (ppb)

Month

Differences in Surface Ozone between

Europe and East Asia Derive regional background

– remove local emissions

Compare:Mace Head (Ireland)Arosa (Switzerland)Mondy (Siberia)Happo (Japan)

East Asian Ozone lower in summer due to Asian monsoon

Ozone 5-10 ppbv higher at Asian sites from autumn to spring

– Why ?

Differences in Surface Ozone between Europe and East Asia

Consider mean difference– Asian sites – European

sites– local emissions removed

Stratospheric influence greater over Asia – driven by subsidence over

Central Asia

Residual largely due to:– emissions over Europe– emissions over Eurasia

Background O3 higher over Asia– implications for air quality

Impacts of European Sources at 100º East

CO– Winter/spring maximum, summer

minimum– Boundary layer impacts greatest

O3

– Spring maximum, summer minimum

– Additional minimum in winter– Greater impacts in mid-

troposphere

Mondy, 52N

Can we detect European influence from the measurements?

Raw obserbational data of O3 and CO at Mondy during 1996-99

Pochanart, Akimoto et. al Atmos. Environ., 2001

O3

CO

Classification based on trajectories

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec20

25

30

35

40

45

50

55

60

a)

Hi Lat

Ozone mixing ratio (ppb)

Month

Europe

Siberia

20 30 40 50 60 70 800

100

200

300

400

500

a) Ozone Europe Siberia High Latitude

Amount of Data (hr)

Ozone mixing ratio (ppb) EU

EU

SI

SI

HL

HL

O3 O3

CO CO

Monthly Mean Data Frequency Distributions (Annual Data)

Comparison of Ozone in European Air mass with Others by Season

Spring Summer Winter

Impact of O3 and CO over Happo, Japan from Europe and N. America

Impacts on O3 and CO over Happo, Japan from Europe and N. America in April 1996

O3 CO

Contribution to Surface O3 at Happo by Difference Sources in April 1996

60 ppbv 1hr av.

European/N.American impacts persist during local pollution episodes (Apr 23-27): affect attainment of air quality standards

Japan EQS for Ox

Seasonal Variation of Trajectory Categorized ozone in Japan

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

10

20

30

40

50

60

70

80

Rishiri 9801-9812

Ozone concentration (ppb)

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

10

20

30

40

50

60

70

80

Okinawa 9501-9612

Ozone concentration (ppb)

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

10

20

30

40

50

60

70

80

Oki 9404-9603

Ozone concentration (ppb)

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

10

20

30

40

50

60

70

80

Ogasawara 9706-9808

Ozone concentration (ppb)

Month

Rishiri

Oki

Okinawa

Ogasawara

Trend of Annual Average Concentration of Ox and Precursors in Tokyo (Average of 23 Stations)

Oxidant Measure Committee Report, Tokyo Metropolitan Government (2005)

Mondy

WaliguanVostochnaya (?)

Long-term measurements needed over Eurasia

• Regional coverage over Asia relatively poor

• Transport from Europe occurs at high latitudes

• More sites needed over Central and Northern Asia

EMEP Sites EANET/ GAW Sites & China

ConclusionsFrom CTM Studie

• Significant European impacts over Central Asia– Average 10-30 ppbv CO, 1-4 ppbv O3

• Only slightly smaller impacts over Japan– Average 2-25 ppbv CO, 0.2-2.5 ppbv O3

– Present during anticyclonic conditions (affect AQ Stds)– N. American influence larger than European in mid-trop

From Observations• Signature of European influence present in O3 and CO

– Still difficult to quantify directly (new methods needed?)