Global Modeling of Organic PM: Global Modeling of Organic PM: State of the Science and Major Gaps State of the Science and Major Gaps Daniel J. Jacob with Rokjin J. Park 1 , Colette L. Heald 2 Tzung-May Fu 3 , Hong Liao 4 and funding from EPRI, EPA, NSF now asst. prof. at Seoul National University now asst. prof. at Colorado State University now asst. prof. at Hong Kong Polytechnic University Caltech, now at Chinese Academy of Sciences
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Global Modeling of Organic PM: State of the Science and Major Gaps Daniel J. Jacob with Rokjin J. Park 1, Colette L. Heald 2 Tzung-May Fu 3, Hong Liao.
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Global Modeling of Organic PM: Global Modeling of Organic PM: State of the Science and Major GapsState of the Science and Major Gaps
Daniel J. Jacobwith Rokjin J. Park1, Colette L. Heald2 Tzung-May Fu3, Hong Liao4
and funding from EPRI, EPA, NSF
1 now asst. prof. at Seoul National University2 now asst. prof. at Colorado State University3 now asst. prof. at Hong Kong Polytechnic University4 Caltech, now at Chinese Academy of Sciences
ORGANIC PM IN STANDARD GEOS-Chem MODELORGANIC PM IN STANDARD GEOS-Chem MODEL
Data filtered againstfire plumes (solid)and unfiltered (dotted)
Model source attribution
TotalBiomass burningAnthropogenicBiogenic SOA
Heald et al. [JGR 2006b]
IRREVERSIBLE DICARBONYL UPTAKE BY AQUEOUS AEROSOLIRREVERSIBLE DICARBONYL UPTAKE BY AQUEOUS AEROSOL
Chamber AMS experiments of glyoxal uptake by Liggio et al. [JGR 2005]Organic aerosol mass growth with time Inferred reactive uptake coefficient
• median = 2.9x10-3 observed for aqueous surfaces; evidence for oligomerization• similar observed for methylglyoxal on acidic surfaces [Zhao et al. ES&T 2006]
glyoxal methylglyoxal
POSSIBLE MECHANISMS FOR DICARBONYL SOA FORMATIONPOSSIBLE MECHANISMS FOR DICARBONYL SOA FORMATION
GAS AQUEOUS
Oligomers
OHOrganic acids
H* ~ 105 M atm-1
Ervens et al. [2004]Crahan et al. [2004]Lim et al. [2005]Carlton et al. [2006, 2007]Warneck et al. [2005]Sorooshian et al. [2006, 2007]
Altieri et al. [2006, 2008]
Schweitzer et al. [1998]Kalberer et al. [2004]Liggio et al. [2005a,b] Hastings et al. [2005] Zhao et al. [2006]Loeffler et al. [2006]
glyoxal
H* ~ 103 M atm-1
methylglyoxal
oxidation
oligomeriz
ation
oli
go
mer
izat
ion
GLYOXAL/METHYLGLYOXAL FORMATION FROM ISOPRENEGLYOXAL/METHYLGLYOXAL FORMATION FROM ISOPRENE
GLOBAL GLYOXAL BUDGET IN GEOS-ChemGLOBAL GLYOXAL BUDGET IN GEOS-ChemIncluding reactive uptake by aq. aerosols + clouds with =2.9x10-3 [Liggio et al., 2005]
Global SOA formation of 6.4 Tg yr-1 (1.0 in clear sky + 5.4 in cloud);compare to 16 Tg yr-1 from terpenes/isoprene by semivolatile mechanism
Indication of a missing marine source in the modelFu et al. [JGR, in press]
SCIAMACHY SATELLITE OBSERVATION OF GLYOXALSCIAMACHY SATELLITE OBSERVATION OF GLYOXAL
• General spatial pattern reproduced over land, SCIAMACHY is 50% higher than model• SCIAMACHY sees high values over oceans correlated with chlorophyll: unidentified marine source?
100 pptv glyoxal in marine boundary layer would yield ~1 g C m-3 SOA;could contribute to observed OC aerosol concentrations in marine air
Fu et al. [JGR, in press]
SIMULATION OF WSOC AEROSOL OVER EASTERN U.S.SIMULATION OF WSOC AEROSOL OVER EASTERN U.S.Water-soluble OC (WSOC) aerosol observations by Rodney Weber (GIT)from NOAA aircraft during ICARTT campaign out of Portsmouth, NH (Jul-Aug 04)
Observed
Model w/ dicarbonyl SOA addedModel w/ standard SOA
Model hydrophilic primary OA
biomass burning plumes excluded Boundary layer data (<2 km)
Fu et al., in prep.
IMPROVE (surface) ICARTT
model w/ dicarbonyls w/out dicarbonyls
Dicarbonyl source in summer is mainly Biogenic (isoprene)
CORRELATIONS OF FREE TROPOSPHERIC WSOC CORRELATIONS OF FREE TROPOSPHERIC WSOC WITH OTHER VARIABLES MEASURED ON NOAA AIRCRAFTWITH OTHER VARIABLES MEASURED ON NOAA AIRCRAFT
ObservedModel with dicarbonyl SOAModel without dicarbonyl SOA
• WSOC is observed to correlate with• toluene and methanol (anthro+bio?)• sulfate (aqueous-phase production?)• alkyl nitrates (photochemistry?)
• Model does not reproduce observed WSOC variability but does better with correlations, particularly when dicarbonyl SOA is included (sulfate, alkyl nitrates)