Effects of Global Change on Air Quality in the United States

Effects of Global Change on Air Quality Effects of Global Change on Air Quality

in the United Statesin the United States

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

Look into the Future with GEOS-CHEM ---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?What will influence the future air quality?

CTM

1. Emission 2. Meteorology

Winds

Convective mass flux

Strat-influx

Meteorological control of air quality (case of Meteorological control of air quality (case of 210210Pb)Pb)July mean surface concentration of 210Pb (fCi/SCM)

Air QualityPollutants

concentration & distribution

Chemistry, transport, deposition, etc

Frame structureFrame structure

Natural Emissions

Anthropogenic Emissions

Pollutants & precursors

GHG

Climate

Radiative forcing

Difference b/w GISS and GEOS – Vertical gridsDifference 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 gridsDifference b/w GISS and GEOS -- Horizontal grids

46 bins 45 bins

GEOS 4x5 GISS 4x5

GISS - “B” Grid GEOS - “A” Grid

( shift in both latitude and longitude direction )( shift in both latitude and longitude direction )

Difference b/w GISS and GEOS -- Convection SchemesDifference b/w GISS and GEOS -- Convection Schemes

GEOS_3 GEOS_4 GISS

Updraft UpdraftEntraining Updraft

Non-entraining Updraft

N/A DowndraftEntraining Downdraft

Non-entraining Downdraft

Detrainment EntrainmentEntraining Detrainment

Non-entraining Detrainment

Different met-fields Different met-fields Different results expected Different results expected

Natural emission sensitive to met-fieldsNatural emission sensitive to met-fields

Natural emission sensitive to met-fieldsNatural emission sensitive to met-fields

Lightning emission sensitive to met-fieldsLightning emission sensitive to met-fields

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

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

Validation against ozonesonde dataValidation against ozonesonde data( July monthly mean )( July monthly mean )

ConclusionsConclusions

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

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

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

Thank you!Thank you!