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

Barkley, Michael P.; Kurosu, Thomas P.; Chance, Kelly; De Smedt, Isabelle; Van Roozendael, Michel; Arneth, Almut LU ; Hagberg, Daniel LU and Guenther, Alex (2012) In Journal of Geophysical Research 117. p.13304-13304
Abstract
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... (More)
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. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Geophysical Research
volume
117
pages
13304 - 13304
publisher
American Geophysical Union
external identifiers
  • wos:000306237700002
  • scopus:84864056400
ISSN
2156-2202
DOI
10.1029/2011JD016827
project
BECC
MERGE
language
English
LU publication?
yes
id
ea550704-6375-4e43-bece-8fd34641e254 (old id 2995002)
date added to LUP
2012-08-21 15:08:05
date last changed
2017-10-29 03:13:49
@article{ea550704-6375-4e43-bece-8fd34641e254,
  abstract     = {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.},
  author       = {Barkley, Michael P. and Kurosu, Thomas P. and Chance, Kelly and De Smedt, Isabelle and Van Roozendael, Michel and Arneth, Almut and Hagberg, Daniel and Guenther, Alex},
  issn         = {2156-2202},
  language     = {eng},
  pages        = {13304--13304},
  publisher    = {American Geophysical Union},
  series       = {Journal of Geophysical Research},
  title        = {Assessing sources of uncertainty in formaldehyde air mass factors over tropical South America: Implications for top-down isoprene emission estimates},
  url          = {http://dx.doi.org/10.1029/2011JD016827},
  volume       = {117},
  year         = {2012},
}