Trans-Eurasian Transport of Ozone and its Precursors

Oliver Wild,

Pakpong Pochanart and Hajime AkimotoFrontier Research Center for Global Change

Yokohama, Japan

Second ICAP Workshop, Oct 21, 2004, Chapel Hill, NC

Trans-Eurasian TransportMotivation

• Trans-Pacific and Trans-Atlantic transport well studied– PEM-West, TRACE-P, ACE-Asia, NARE, ITCT

• Trans-Eurasian transport less well understood due to location, landmass and meteorology

• 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?

Key Foci: Air Quality, Oxidizing Capacity, Climate

Continental Outflow in Spring

N. American O3

European O3

4 ppbv isosurface of O3 in April

Background O3 over Japan is rising

• Rising NOx/CO/NMHC emissions over Asian mainland

• What are the impacts from further afield?

Ozone Over Japan

Ohara and Sakata 2003: Data from 341 monitoring stations

FRSGC/UCI Global CTM

• Tropospheric gas-phase chemistry

• Linearized stratospheric chemistry for O3

• Emissions for 1990 from EDGAR v2.0

• Driven by 2 sets of meteorology:

Meteorology Resolution

GISS II’ GCM 4º x 5º x 9 levels 3 hrs

ECMWF-IFS 1996 5.6º x 5.6º x 19 levels 3 hrs

O3 and CO over Eurasia

Mace HeadZugspitze

MondyHappo

Trajectories Arriving at 100°E

viz. Newell and Evans [2000]

Trajectories Arriving at 100°E

viz. Newell and Evans [2000]

Export of Oxidants from Europe

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

Impacts at Mondy (52ºN, 101ºE)

CO CO

O3 O3

Impacts on CO and O3 over Japan

Impacts on CO over Japan in April 1996

• Patterns of European and N. American influence very similar

• Transport pathways are similar

• European influence about 25% greater

Impacts on CO over Japan in April 1996

10-8 kg/m2/s

Impacts on O3 over Japan in April 1996

• Patterns of European and N. American influence appear quite different

• Transport pathways are similar, but timing of events is different

• European influence on O3 is smaller than that from N. America

Impacts on O3 over Japan in April 1996

10-9 kg/m2/s

Impacts on O3 over Japan in April 1996

Impacts on O3 over Japan in April 1996

Surface O3 at Happo

60 ppbvJapan 1hr std

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

Annual Mean Lifetimes of CO and O3

CO O3Production Efficiency

European 82 days 18 days 6.7

N. American 61 days 19 days 6.7

East Asian 62 days 21 days 10.5

South Asian 56 days 25 days 19.2

Tropospheric Mean

55 days 30 days 30

Annual Global Mean Profiles

• Different impacts on OH and hence on CH4

• Expect different climate responses

Annual Mean Chemical Tendencies

ConclusionsImpacts on Central Asia• High-latitude flow round Siberian High and Tibet

• European impacts average 10-30 ppbv CO, 1-4 ppbv O3

• European influence on O3 suppressed in winter

Impacts on Japan• Significant background enhancements in O3 and CO

• Modest surface O3 impacts, but will affect Air Quality Stds

• N. American influence larger than European in mid-trop

Global Impacts• European emissions may lead to net decrease in OH

• Significantly different indirect climate effects expected

Mondy

HappoWaliguanVostochnaya Taishan

Huangshan

Huashan

Long-Term Measurements over Asia• Regionally polluted sites over China now operational

• Transport from Europe occurs at high latitudes

• More sites needed over Central and Northern Asia

Measurement Sites over Eurasia