In Cooperation with the IAMAS Commission on

Atmospheric Chemistry and Global Pollution (CACGP)

The International Global Atmospheric Chemistry ProjectA Core Project of the

International Geosphere-Biosphere Programme (IGBP)

IGBP Steering Committee4-7 March 2006, Pune, India

Phil Rasch

What is IGAC?

• Focused on understanding the changing chemical composition of the earth’s atmosphere, particularly the troposphere. Implementation:

• 1. Endorsement & support of TASKSTASKS: Focused scientific question 3-4 year timetable QA/QC & public data access Educational & capacity building efforts. End-point: peer-reviewed manuscript(s).

• 2. Co-sponsorship of WORKSHOPSWORKSHOPS: Review/assess current state of knowledge on an issue Define a framework for resolving open questions Produce a white paper or similar with workshop results

• 3.3. Top-down Top-down INITIATIVESINITIATIVES:: Atmospheric Chemistry & Climate Mega-cites Integration Aerosols, Clouds & Precipitation

Task: AICI (Air-Ice Chemical Interactions)

• Campaigns at South Pole and Halley Bay (Antarctica) in 2004-2005 to study: tropospheric ozone

depletion ice photochemistry halogen cycles

• In data analysis/paper-writing stage

• New: AICI-IPY (International Polar Year)

South Pole

NO > 200 pptv (model expectation 1-5 pptv)OH ~2 x 106 molecules cm-3

Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of

Climate, Chemistry, Aerosols, and Transport (POLARCAT)

• International Polar Year project

• Specific foci are: pollution transport to the Arctic aerosol radiative effect in the Arctic boreal forest fires (with SPARC) chemistry of Arctic (with AICI)

• Activities ongoing to secure funding for the experiments and aircraft and ship time

Task: Mega-cities Asia

• Integrated approach air to quality & climate

• Japan, China, South Korea and China-Taipei

• Focus on: Consistency in

measurements across the region (instrument intercomparison)

Communication Data sharing

IMPACT: Integrated Measurement Programfor Aerosol and Oxidant Chemistry in Tokyo

Task: Intercontinental Transport and Chemical Transformation

(ITCT-Lagrangian 2k4)

• Focus: transformation and removal processes of aerosols, oxidants and precursors during intercontinental transport

• “-2k4” based on Summer 2004 field campaign: Trans-Atlantic transport Pseudo-Lagrangian with

platforms on both sides of the Atlantic

• In the data analysis / paper-writing stage

2004 field campaignFour aircrafts used to track pollutant

plumes in combination with modelling,satellite, surface data

Task: African Monsoon Multidisciplinary Analysis

(AMMA)• Atmospheric chemistry

component of the larger AMMA project

• Larger AMMA project focus: Integrated study of land

surface, emissions, monsoon, human dimensions

• Focus of the IGAC/iLEAPS AMMA Task will be the Enhanced Operation Period, 2005-2007

Task: Deposition of Biologically Important Trace Species

(DEBITS II)• Builds on a project of the IGAC

first phase

• Study of wet and dry deposition of chemical species

• Second phase emphasis: data synthesis Long-term, uniform

measurements inclusion of new

parameters

• Three study regions

• Coordinated with WMO-GAW Precipitation Chemistry Activity

Composition &Acidity of AsianPrecipitation(CAAP)

Large ScaleBiosphereAtmosphereExperimentIn Amazonia(LBA)

IGACDEBITSAfrica(IDAF)

Task: Global HO Systematic Tests (GHOST)

• Addressing the problem of quantifying the global distribution of the hydroxyl radical OH through alternative tracers

• In the very early stages of development…

Workshops organized

• Aerosol Indirect Effect Workshop 5-7 January 2005, Manchester, England (Co-sponsored by

IGAC, NOAA and NASA)

• Processes Controlling the Chemical Composition of the Mid-latitude UTLS May 18-20, 2005, Mainz, Germany (Co-sponsored by IGAC

& SPARC

• Aerosol Formation Workshop August 15-17, 2005; Hyytiälä, Finland (Co-sponsored by

iLEAPS, IGAC, SOLAS, ACCENT, BACCI)

• The routes for organics oxidation in the atmosphere and its implications to the atmosphere January 7-11, 2006, Alpe D’Huez, France (Co-sponsored

by SPARC, IGAC, ACCENT)

IGAC International Conferences

• Atmospheric chemistry observations and their integration and synthesis

• Chemical weather on regional to global scales: simulations, analysis and impacts

• Long-range transport and chemical transformations

• Aerosol-cloud interactions and climate implications

• Aerosol chemistry and the interactions between aerosols and gas phase chemistry

• Reactive chemistry and exchanges between the MBL and the ocean mixed layer.

• Land-atmosphere biogeochemical cycles • Biomass burning emissions and impacts

on atmospheric chemistry• Metro-Agro-Plexes • Chemistry of the UT/LS region (A Joint

IGAC-SPARC Session)• Interface processes between the Ocean,

Atmosphere, Sea Ice, and Snow in Polar Regions

Capetown, SA, 17th – 23rd September 2006 Joint CACGP / IGAC / WMO Symposium

Beijing, China9-12th November 2006

Earth System Science Partnership

• Chemistry and Climate in the Upper Troposphere/Lower Stratosphere (UT/LS) Region (SPARC-IGAC)

• Too many to list….

Connections IGAC / this workshop

• WCRP/IGBP Atmospheric Chemistry & Climate Initiative (driven from the SPARC/IGAC level)

• Aerosols, Clouds & Precipitation Initiative (iLEAPS, IGAC, GEWEX)

• Specific science issues (a few thoughts): The small crystal puzzle Potentials for mixing line analysis in the troposphere Ozone …

Atmospheric Chemistry and Climate Initiative: Rationale

•Two objectives of the project:• Understanding the role of emissions via atmosphere chemistry on atmospheric composition• relating the concentrations to radiative forcings/climate change

Understanding Climate: Understanding and quantifying Processes!

ProcessesSources

PrecursorsAbundancecomposition

RadiativeForcing/

Health effects

Properties/Processes

ClimateChemistry, other factors (including policy)Chemistry

•Modeling these processes in Climate and Earth System Models are needed.

Providing the ability to do it, with respect to chemistry, is the aim of AC&C.

Choice of First Problem to be tackled by

Task Force • Define an important, tractable problem:

Modeling Project CCM-Val extension to the troposphere

• Emphasis will be on: Aerosol (formation, transformations, cloud interaction, photolysis,

reactivity) Ozone Deposition processes

forcings & feedbacks

• Problems relevant to many aspects of climate change AND will yield short-term needed info

• Common to all advanced next generation models for Climate Change

Studies.

Products• Statements about component processes that contribute

most to uncertainty in radiative forcing and climate change (e.g., emissions, formation mechanisms, removal processes, interaction with other components [e.g. land, ocean, society])

• Identification of metrics that provide insight into model behavior w.r.t. chemistry/climate interactions

• Pointers to more promising (less desirable) formulations for process representation

• Identify opportunities for programs and projects to contribute to improving models

Use of mixing lines to diagnose convection

Paluch (1997), conserved quantities under non-precipitation, phase change

Fischer et al 2000, tracer/tracer correlations as diagnositics of strat/trop mixing

The small ice crystal puzzle(observations)

David Mitchell, Phil Rasch, Paul Lawson

Small Ice Crystal (Implications)

• amplitude of small mode Brighter in solar Fall much more slowly

• Rate of supply of massof water substance to TTL differs dramatically!

• Along with the water goes tracers!

Ice Water Content S

edim

enta

tion

velo

city

Heymsfield et al class

Mitchell et al class

Summary• Role of TTL is an important topic for climate and

chemistry• IGAC is interested in participating

~THE END ~

The Phase 1 task: Modeling Study

• Many modeling centers have already built or are building higher resolution global models with interactive chemistry

• Help the centers to systematically: Define gaps in current representations Assist in filling those gaps Define simulations relevant to an inter-comparison activity

Emissions, boundary condition Verification/validation datasets

compare model behavior Define metrics

identify deficiencies Archive simulation outputs

A path to Nirvana

Complete chemistry in a fully coupled Earth System model

Need:Fully characterized and predictable (modeled) emission.

Understanding of processes that predict formation and transformations of gas phase and aerosol species, and properties of aerosols species.

Improvements in other components- e.g., transport, convection, exchange with biosphere and oceans, ….

Complete representation of the all critical species and their interaction- including formation, transformation, and properties of aerosols

A HIGHLY UNDERSAMPLED ATMOSPHERE.

Gas phase chemistry processes in models OK

Inadequate representation of aerosol production, removal, transformation, and properties.

Poorly understood & characterized emissions.

Poorly understood and characterized removal processes.

A path to Nirvana, continued

Complete chemistry in a fully coupled Earth System model

Where other WCRP/IGBP programs provide needed information:

SPARC- stratosphere and UT/LS chemistry

IGAC- Lower tropospheric chemistry

SOLAS- exchanges

Emission- AIMES, ILeAPS, CLiC?….

Dynamics and transport- WCRP projects

Others…

Other modulations and changes: IHDP, DIVERSITAS….

Chemistry & Climate change predictions

•Most anthropogenic forcing agents are controlled by chemical processes.•Understanding, quantifying, and accurately representing them in models is essential for assessing human influence on climate.•Many forcing agents are also pollutants! (“win-win” options? “win-lose” consequence?)•Lifetimes determine policy decision information.