Aerosol Simulation Over Aerosol Simulation Over North AmericaNorth America

Aaron Van DonkelaarAaron Van Donkelaar

April 2005April 2005

Remote Sensing of Surface Particulate Remote Sensing of Surface Particulate MatterMatter

extZQ

rM

3

4

• M –mass loadingM –mass loading

• ρρ – particle mass density – particle mass density

• r – effective radius (AERONET)r – effective radius (AERONET)

• ττ – aerosol optical depth – aerosol optical depth (MODIS/GEOS-CHEM)(MODIS/GEOS-CHEM)

• QQextext – extinction factor (AERONET) – extinction factor (AERONET)

• Z – air mass height (GEOS-CHEM)Z – air mass height (GEOS-CHEM)

GEOS-CHEM GEOS-CHEM Underestimates Underestimates

AODAOD

MODIS, July 2002

GEOS-CHEM v7-02-01, July 2002

Optical Depth at 550nm [unitless]

AERONET, July 2002

GEOS-CHEM Organic Carbon Too LowGEOS-CHEM Organic Carbon Too Low

GEOS-CHEM v7-02-01 Mass Concentrations [ug/m3]

July 2002

IMPROVE Mass Concentrations [ug/m3]

July 2002

Summer Organic Carbon BiasSummer Organic Carbon Bias

GEOS-CHEM – IMPROVE [ug/m3]

May, 2002 June, 2002

September, 2002

April, 2002

July, 2002 August, 2002

Low OC Yield from IsopreneLow OC Yield from Isoprene

• Matsunaga, S. N. et al. Matsunaga, S. N. et al. Isoprene oxidation products are a Isoprene oxidation products are a significant atmospheric aerosol componentsignificant atmospheric aerosol component. . in prepin prep..

• Claeys, M. et al. Claeys, M. et al. Formation of secondary organic aerosols from Formation of secondary organic aerosols from isoprene and its gas-phase oxidation products through reaction isoprene and its gas-phase oxidation products through reaction with hydrogen peroxidewith hydrogen peroxide. Atmospheric Environment.. Atmospheric Environment.

• Claeys, M. et al. Claeys, M. et al. Formation of Secondary Organic Aerosols Formation of Secondary Organic Aerosols Through Photooxidation of IsopreneThrough Photooxidation of Isoprene. Science.. Science.

Recent literature has proposed OC yield from isoprene

Guenther has suggested specific pathwaysAssume 1% to 3% Yield

OC from Isoprene Corrected BiasOC from Isoprene Corrected Bias-remaining bias from biomass burning regions-remaining bias from biomass burning regions

GEOS-CHEM – IMPROVE [ug/m3]

April, 2002 May, 2002 June, 2002

July, 2002 August, 2002 September, 2002

OC Does Not OC Does Not Correct AOD BiasCorrect AOD Bias

MODIS, July 2002

GEOS-CHEM w Isoprene Yield, July 2002

Optical Depth at 550nm [unitless]

AERONET, July 2002

Preliminary Vertical Structure Evaluation - ICARTTPreliminary Vertical Structure Evaluation - ICARTTNH4

NO3 OC

SO4GEOS-CHEM

PILS

AMS

SummarySummary

• Low yield OC production from isoprene corrects Low yield OC production from isoprene corrects seasonal biasseasonal bias

• Biomass burning inventories for 2002 are neededBiomass burning inventories for 2002 are needed

• Continue to evaluate model vertical structure Continue to evaluate model vertical structure using ICARTT datausing ICARTT data

AcknowledgementsAcknowledgements

• Randall MartinRandall Martin

• Alex GuentherAlex Guenther

• Rokjin ParkRokjin Park

• Solene TurquetySolene Turquety

• Easan DruryEasan Drury