Assessing sources of uncertainty in formaldehyde air mass factors over tropical South America: Implications for top-down isoprene emission estimates

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Authors
Barkley, M.P.
Kurosu, T.P.
Chance, K.
De Smedt, I.
Van Roozendael, M.
Arneth, A.
Hagberg, D.
Guenther, A.
Discipline
Earth and related Environmental sciences
Subject
Atmospheric chemistry
Formaldehyde
Spectrometers
Air mass factor
Chemistry transport model
Isoprene emission
Ozone monitoring instruments
Scanning imaging absorption spectrometer for atmospheric chartography
Seasonal variability
Sensitivity tests
Sources of uncertainty
South America
Surface albedo
Topdown
Vertical column densities
Vertical columns
Atmospheric aerosols
aerosol composition
air mass
albedo
atmospheric pollution
emission inventory
EOS
formaldehyde
isoprene
SCIAMACHY
seasonal variation
uncertainty analysis
South America
Audience
Scientific
Date
2012Metadata
Show full item recordDescription
We use a nested-grid version of the GEOS-Chem chemistry transport model, constrained by isoprene emissions from the Model of Emissions of Gases and Aerosols from Nature (MEGAN), and the Lund-Potsdam-Jena General Ecosystem Simulator (LPJ-GUESS) bottom-up inventories, to evaluate the impact that surface isoprene emissions have on formaldehyde (HCHO) air-mass factors (AMFs) and vertical column densities (VCDs) over tropical South America during 2006, as observed by the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) and Ozone Monitoring Instrument (OMI). Although the large-scale seasonal variability of monthly mean HCHO VCDs is typically unaffected by the choice of bottom-up inventory, large relative differences of up to ±45% in the HCHO VCD can occur for individual regions and months, but typically most VCD differences are of order ±20%. These relative changes are comparable to those produced by other sources of uncertainty in the AMF including aerosols and surface albedo, but less than those from clouds. In a sensitivity test, we find that top-down annual isoprene emissions inferred from SCIAMACHY and OMI HCHO vertical columns can vary by as much as ±30–50% for each instrument respectively, depending on the region studied and the a priori isoprene emissions used. Our analysis suggests that the influence of the a priori isoprene emissions on HCHO AMFs and VCDs is therefore non-negligible and must be carefully considered when inferring top-down isoprene emissions estimates over this, or potentially any other, region.
Citation
Barkley, M.P.; Kurosu, T.P.; Chance, K.; De Smedt, I.; Van Roozendael, M.; Arneth, A.; Hagberg, D.; Guenther, A. (2012). Assessing sources of uncertainty in formaldehyde air mass factors over tropical South America: Implications for top-down isoprene emission estimates. , Journal of Geophysical Research: Atmospheres, Vol. 117, Issue 13, D13304, DOI: 10.1029/2011JD016827.Identifiers
scopus: 2-s2.0-84864056400
Type
Article
Peer-Review
Yes
Language
eng