In Cooperation with the IAMAS Commission on Atmospheric Chemistry and Global Pollution (CACGP) The International Global Atmospheric Chemistry Project A Core Project of the International Geosphere- Biosphere Programme (IGBP) IGBP Steering Committee 4-7 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: TASKS1. Endorsement & support of TASKS:  Focused scientific question  3-4 year timetable  QA/QC & public data access  Educational & capacity building efforts.  End-point: peer-reviewed manuscript(s). WORKSHOPS2. Co-sponsorship of WORKSHOPS:  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.Top-down INITIATIVES:3.Top-down INITIATIVES:  Atmospheric Chemistry & Climate  Mega-cites Integration  Aerosols, Clouds & Precipitation

Task: AICI (Air-Ice Chemical Interactions) Campaigns at South Pole and Halley Bay (Antarctica) in 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 10 6 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 Program for 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 campaign Four 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,

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 Asian Precipitation (CAAP) Large Scale Biosphere Atmosphere Experiment In Amazonia (LBA) IGAC DEBITS Africa (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, China 9-12 th 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! Processes Sources Precursors Abundance composition Radiative Forcing/ Health effects Properties/ Processes Climate Chemistry, 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 mass of water substance to TTL differs dramatically! Along with the water goes tracers! Ice Water Content Sedimentation velocity 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.