# Presentation: 001639

## Internationally Coordinated Modeling Activities:  HTAP and AC&C

**Goddard Aerosol Update**

**Internationally Coordinated Modeling Activities:  ****HTAP ****and**** ****AC&C**

**This list is soooo long !!**

**Year of the Pig 2007**

**&**

## Memory Test – Memorize these acronyms in 30 seconds

| ACCENT-MIP | Atmospheric Composition Change: The European Network for Excellence – Model Intercomparison Project |
| --- | --- |
| AEROCOM | Aerosol Comparisons between Observations and Models |
| AC&C | Atmospheric Chemistry and Climate Initiative |
| CCM-Val | Chemistry-Climate Model Validation |
| CCSP | Climate Change Science Program |
| HTAP | Hemispheric Transport of Air Pollution |
| IGAC | International Global Atmospheric Chemistry |
| IGBP | International Geosphere-Biosphere Programme |
| IPCC | Intergovernmental Panel on Climate Change |
| LRTAP | Long-Range Transboundary Air Pollution |
| SPARC | Stratospheric Processes And their Role in Climate |
| WCRP | World Climate Research Programme |
| WMO | World Meteorological Organization |

## HTAP: Hemispheric Transport of Air Pollution

**HTAP:**
**A United Nations Task Force created in December 2004, under the Convention on Long-Range Transboundary Air Pollution (LRTAP)**
**Led by the European Community and the United States (Co-Chairs: Andre Zuber, EC; Terry Keating, USEPA)**
**Purpose: To develop a fuller understanding of intercontinental transport of ozone, aerosols, and other pollutants and their impact**
**Task Force includes experts from emission, observation, and modeling communities**

## HTAP Modeling Activities

**The TF HTAP is conducting a series of model evaluation and intercomparison experiments to**
**Estimate intercontinental source-receptor relationships **
**Improve our understanding of the variability and uncertainty in current model estimates **
**Guide future model developments**
**Currently >20 global and regional models are involved in HTAP experiments including GOCART, GMI, MOZART, GEOS-CHEM, CAM-CHEM from the U.S. and many others from Europe**
**Interim report due 2007, assessment report due 2009 **

- _[http://aqm.jrc.it/HTAP/](http://aqm.jrc.it/HTAP/)__ for model experiments_
- _[http://www.htap.org/](http://www.htap.org/)__ for general information_

## HTAP model experiment regions

**Assessing the impact of pollutants emitted from major source regions on other areas.  Major anthropgoenic source regions: North America (NA), Europe (EU), East Asia (EA), South Asia (SA).**

**Can we blame China for our bad air ?**

**AEROCOM will conduct additional multiple model experiments to assess dust and smoke transport.**

## AC&C: Atmospheric Chemistry and Climate Initiative

**AC&C:**
**Endorsed in March 2006 as a joint effort of WCRP and IGBP**
**Coordinated by Phil Rasch (Co-chair of IGAC/IGBP) and A.R. Ravishankara (Co-chair of SPARC/WCRP)**
**Purpose: Coordination of defining a common set of scientific themes and facilitating their execution**
**Building upon existing international modeling activities including **
**CCM-Val (stratospheric chemistry)**
**AEROCOM (aerosols)**
**ACCENT-MIP (tropospheric chemistry)**

**Even me can feel climate is changing**

## AC&C Phase I Activities

_**Long-term simulation:**_** **
**20-25 year hindcast of tropospheric ozone and aerosols.**
_**Understanding processes:**_** **
**distribution of aerosols/gases between 5km and tropopause.**
_**Aerosol, Cloud, Chemistry:**_** **
**improving their interactions in models.**
_**Future Scenarios:**_** **
**experiments for IPCC AR5.**

## WCRP-SPARC/IGBP-IGAC Atmospheric Chemistry and Climate Initiative

**“****Tropos Chem”**
- (tropospheric gas-phase chem)

**CCM-Val **
- (stratospheric gas-phase chemistry)

_***AC&C Research Activities***_

**AEROCOM**
- (tropospheric aerosols)

_***Research Implementation Bodies***_

**1) 20 year hindcast for tropospheric gases/aerosols**
**2) What controls the distribution of troposhperic aerosols/gases?  (Step 1: Focus on 5km to ****tropopause distribution)**
**3) Cloud/aerosol/chemical interactions**
**4) Future scenarios; sensitivities & uncertainties**

**Can some human tell me what’s going on?**

## Who are funding these activities?

**No funding from any “international” organizations**
**The success of these activities is contingent on buy-in from the scientific community, including us**
**By participating, we take advantage of the community as well**
**Share progresses on model improvement and development**
**Better evaluate the model performance**
**Better access to emission, observations, etc.**
**More relevant to international community**

**NASA ??**

## How can these model exercises help aerosol missions and science?

**The ensemble of model results are proven to be more robust than a single “best” model (if there is any).  Therefore, these exercises can be used for**
**Analyzing data from past and current missions to better understand global and regional aerosol trends, emissions, processes, and impacts**
**Identifying common needs or problems among the models that can be used to recommend or emphasize future observation priorities**
**Forming an international assessment body (e.g., IPCC, WMO, CCSP) providing guidance for research and policies**

**Wow ! This is so cool !**