Effects of Global Change on Air Quality in the United States

• Shiliang Wu, Harvard
• 2^nd GEOS-CHEM users’ meeting
• Apr 5, 2005

Look into the Future with GEOS-CHEM ---

Global Change and Air Pollution (GCAP)

A collaborative interdisciplinary project involves groups from Harvard, Caltech, NASA/GISS, DOE/ANL, U.Tenn.

Harvard Team:

Daniel Jacob, Loretta Mickley, Shiliang Wu

Great thanks Bob Yantosca for supportive work!

What will influence the future air quality?

1. Emission

2. Meteorology

Meteorological control of air quality (case of ²¹⁰Pb)

July mean surface concentration of ²¹⁰Pb (fCi/SCM)

Frame structure

Difference b/w GISS and GEOS – Vertical grids

GEOS_3: 48 layers

GEOS_4: 55 layers

GISS II’: 23 layers

Difference b/w GISS and GEOS -- Horizontal grids

46 bins

45 bins

GEOS 4x5

GISS 4x5

( shift in both latitude and longitude direction )

Difference b/w GISS and GEOS -- Convection Schemes

Different met-fields 🡪 Different results expected

Natural emission sensitive to met-fields

Natural emission sensitive to met-fields

Lightning emission sensitive to met-fields

Afternoon tracer conc. over U.S. (surface layer)

Afternoon tracer conc. over U.S. (zonal mean)

Validation against ozonesonde data

( July monthly mean )

Conclusions

• 1. The performance of the GCAP model looks good and should be capable of the mission.

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• 2. There still might be (minor) improvements in the near future.

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• 3. GEOS-CHEM is (to some extent) flexible and easy going.

Thank you!