# Presentation: 266161

## Meteorological Analyses and Chemical Forecasting in Support of the Aura Validation Missions

- S. Pawson, J. E. Nielsen, W.-W. Tan, A.M. da Silva
- Global Modeling and Assimilation Office
- S. Randolph Kawa, Peter Colarco, Mian Chin
- Atmospheric Chemistry and Dynamics Branch
- Solène Turquety, Daniel Jacob
- Harvard University

## GMAO Involvement 

- History of mission support from DAO and GMAO: provision of meteorological analyses
- GMAO data have been used for off-line chemistry modeling in support of missions
- Technical advances have facilitated development of on-line chemical modeling: accurate and efficient approach
- Intex-NA mission used as a proof of concept: linearized Harvard chemistry run at GMAO in near-real time; results provided to Harvard/Seattle for the mission support

## Pollution Features: 7/22/2005 

- 48-hour forecasts of CO, on-line in GEOS-4

- N. American Fossil Fuels

- Asian Emissions

- N. American Biomass Burning

- Total forecast CO

## Results from Intex-NA 

- Demonstration that GEOS-4 can quantify pollutant distributions in relation to local emissions and long-range transport from remote sources
- Quantitative uncertainty related to integrity of model processes, especially sub-grid transport and source-sink uncertainties: _research pathway for GMAO_
- Highlighted technical capabilities of GMAO’s systems: timely delivery of forecast constituents to field missions a couple of hours after meteorological analyses are complete

## GMAO Operations: First-Look Stream

- 5-day chemical forecast

## EOS-Aura Missions Supported 

| Mission | System | Constituents |
| --- | --- | --- |
| Intex-NA
Summer 2004 | GEOS-4 1.251L55
Linearized chemistry
EOS BB “sources” | Tropospheric & stratospheric O3; seven “tagged” CO tracers; CO2; sulfate aerosol |
| Polar Avé
Jan-Feb 2005 | GEOS-4 2.52L55
Full strat. chemistry | Douglass-Kawa middle atmospheric chemistry  |
| Houston Avé
June 2005 | GEOS-4 1.251L55
Linearized chemistry
GOCART aerosols
EOS BB “sources” | “Tagged” CO tracers; 
Multiple aerosols  |

- Missions supported using versions of GMAO’s models with modules for constituents implemented “on line”

## Evaluation of PAVE Forecasts

- Error growth in temperature, at 2-, 5- and 10-day forecast times - implication for PSCs
- Accuracy of features in forecasts at two days - suitability for flight planning
- Highlight the fact that certain dynamical patterns are quite well predicted, even at 10-day timescales, with correct transport mechanisms

## Analyzed, Forecast TNP at 52hPa

- Summary
- Forecasts of North-Pole temperature are not consistently biased warm or cold
- Forecasts with different lead times have similar tendencies – dependence on dynamical regime
- Errors tend to grow with increasing forecast time (not really a surprise!)

## Impacts on PSC Forecasts

- Overview:
- PSCs calculated with simple microphysics approach
- T dependence of NAT cloud formation makes the total amount of condensed HNO3 a useful integrated measure of impacts of temperature error in cold regions
- There are substantial errors in the 10-day forecasts, but skill is quite high at 5 days
- 10-day error not consistently warm or cold (good for climate studies)

## February 18-28: forecasts

- Temperature

- Ozone

- Methane

## Forecasts Ending on Feb 22, 2005

- Forecasts consistently show the development of a wave-3 structure, with well-defined transport features in ozone that are not seen in meteorological fields

## Summary

- GEOS-4 medium-range forecasts are accurate enough for field mission support (flight planning)
- Constituent forecasts contain information on transport that supplements the met. fields
- The ten-day forecasts give positive indications for chemistry-climate studies:
- No substantial bias in PSC formation
- Development of realistic vortex features
- Transport into vortex (no NH ozone hole!)

## Future

- Experience gained with GEOS-4 in this study will be invaluable as we evaluate GEOS-5: basic issues of model performance and transport are addressed
- Ongoing work addresses quality of our analyses when compared to the in-situ data and the Aura instruments: again, this is a benchmark for GEOS-5 evaluation
- Mission support promotes unique type of scrutiny for GMAO products