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Intercontinental Transport and Chemical Transformation (ITCT) An Activity of the International Global Atmospheric Chemistry Project (IGAC) Today (briefly): • The inception of ITCT • Preliminary findings (the scientific basis of ITCT) • The principle science questions
An Activity of the International Global Atmospheric Chemistry Project (IGAC)
• The inception of ITCT
• Preliminary findings (the scientific basis of ITCT)
• The principle science questions
• The strategy and tools
• Outline of planned research
(More detailed presentations at this meeting)
The International Global Atmospheric Chemistry (IGAC)project was established (1988)
to investigate the impact of chemistry on global climate change. (ozone and aerosols)
Tokyo Workshop (March 16-17, 2000, Frontier Research Systems for Global Change).
Steering committee formed; white paper accepted by IGAC; ITCT steering committee
met (June 6 -7) and outlined a science plan.
ITCT was formulated with the recognition that climate change had regional as well as global dimensions and ozone and aerosols had air quality, as well as, climate change implications.
Focus of ITCT:
Focus on shorter-lived pollutants; ozone, aerosols.
Much of the anthropogenic sources are in the Northern Hemisphere.
For short-lived species, the ITCZ represents a line of demarcation that separates the world into two unique chemical zones; the Northern, where most of the land is, and the Southern, which is dominated by water.
Since compounds are short-lived, most of the impact
is in the Northern Hemisphere.
The public concern with the chemical aspects of these species is strongly involved with air-quality (human and ecosystem impacts as opposed to climate). ITCT will try to address both regional climate and air-quality concerns.
White papers available.
The Scientific Basis of ITCT from a Transatlantic Perspective
(c.f., Parrish and Jacob this afternoon)
Transported to the Remote
There is a strong seasonal
variation in the anthropogenic
influence on the tropospheric
Ozone mixing ratio (ppbv)
(Parrish et al.)
mechanism for the transport of
continental pollution to mid and
upper troposphere of the North
Atlantic (Angevine et al.).
Transport enhanced by fronts.
Layers can be dominated by anthropogenic pollution or by
stratospheric O3 (c.f., Stohl et al.).
Identification of controlling
(Topics described in posters: Cooper, McCaffery and McKeen.)
formation over the North Atlantic
Emissions from forest fires influence
air-quality on a hemispheric scale.
CO (Wotawa and Trainer)
O3, NOx (McKeen et al.)
(Science Questions, Approach, Plans ITCT from a Transatlantic Perspective)
What are the export fluxes of oxidants,
aerosols, and their precursors from
the Northern Hemisphere continents to the global atmosphere?
What is the ultimate fate of these
substances exported to the global
What are the impacts of intercontinental transport in the Northern Hemisphere on
surface air quality?
What are the impacts of changing emissions on regional and global atmospheric
chemistry, composition, and climate?
What are the impacts of climate variability on regional and global atmospheric chemistry and composition?
In order to quantify intercontinental transport and chemical transformation observations and models must be integrated.
CONCENTRATIONS AND FLUXES
THE STRATEGY AND TOOLS
Global and continuous but
few species, low resolution
Question - HOW
high resolution but spatially limited
High resolution, targeted flights
provide critical snapshots
for model testing
2001 - 2002: APARE (ACE and TRACE) interpretation.
2002 - :North American inflow experiment, scooping study and interpretation. Planning further inflow out flow experiments.
measurements at other locations.
3. 2002 - : Planning future inflow/outflow experiments.
Exchange with Polar and Tropical Regions
OUTLINE OF PLANNED RESEARCH