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Top‐Down CO Emissions Based On IASI Observations and Hemispheric Constraints on OH Levels
Author(s) -
Müller J.F.,
Stavrakou T.,
Bauwens M.,
George M.,
Hurtmans D.,
Coheur P.F.,
Clerbaux C.,
Sweeney C.
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl076697
Subject(s) - hydroxyl radical , environmental science , carbon monoxide , northern hemisphere , atmospheric sciences , trace gas , inversion (geology) , atmospheric chemistry , atmospheric sounding , hydrocarbon , southern hemisphere , meteorology , remote sensing , chemistry , ozone , geology , climatology , radical , physics , paleontology , biochemistry , organic chemistry , structural basin , catalysis
Abstract Assessments of carbon monoxide emissions through inverse modeling are dependent on the modeled abundance of the hydroxyl radical (OH) which controls both the primary sink of CO and its photochemical source through hydrocarbon oxidation. However, most chemistry transport models (CTMs) fall short of reproducing constraints on hemispherically averaged OH levels derived from methylchloroform (MCF) observations. Here we construct five different OH fields compatible with MCF‐based analyses, and we prescribe those fields in a global CTM to infer CO fluxes based on Infrared Atmospheric Sounding Interferometer (IASI) CO columns. Each OH field leads to a different set of optimized emissions. Comparisons with independent data (surface, ground‐based remotely sensed, aircraft) indicate that the inversion adopting the lowest average OH level in the Northern Hemisphere (7.8 × 10 5 molec cm −3 , ∼18% lower than the best estimate based on MCF measurements) provides the best overall agreement with all tested observation data sets.