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GEOPHYSICAL RESEARCH LETTERS,
VOL. 30, NO. 17,
1881,
doi:10.1029/2003GL017167,
2003
Biogenic methanol and its impacts on tropospheric oxidants
Xuexi Tie
National Center for Atmospheric Research (NCAR), Boulder, Colorado, USA
Alex Guenther
National Center for Atmospheric Research (NCAR), Boulder, Colorado, USA
Elisabeth Holland
National Center for Atmospheric Research (NCAR), Boulder, Colorado, USA
Abstract
We use a global chemical transport model (MOZART-2) to estimate the effects of surface emissions of methanol on tropospheric
oxidants. The importance of methanol in tropospheric chemistry is two fold. First, methanol has a relatively large surface
emission with an estimated global emission of 70 to 350 Tg methanol/year. The estimated methanol flux is comparable to other
major hydrocarbon surface emissions such as isoprene and total monoterpenes, but the chemical lifetime of methanol is several
days (in the boundary layer) to a few weeks (in the upper troposphere), which is much longer than the chemical lifetime of
isoprene or monoterpenes (For example, the chemical lifetime of isoprene is about 2 hours). With a surface emission of 104
to 312 Tg methanol/year (encompasses estimated uncertainty in methanol emissions), the calculation shows that on average,
the inclusion of methanol emission produces approximately 1–2% increase in O3, 1–3% decrease in OH, 3–5% increase in HO2, and 3–9% increase in CH2O globally. The maximum perturbation to the oxidants occurs in the tropical upper troposphere. However, the uncertainty associated
with current methanol emission estimates produces significantly different model predictions of tropospheric oxidant distributions.
Received 20
February
2003;
accepted 14
July
2003;
published 4
September
2003.
Index Terms: 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 0325 Atmospheric Composition and Structure: Evolution of the atmosphere.
Read Full Article (file size: 425065 bytes) Cited by
Citation: Tie, X., A. Guenther, and E. Holland
(2003),
Biogenic methanol and its impacts on tropospheric oxidants,
Geophys. Res. Lett.,
30(17),
1881,
doi:10.1029/2003GL017167.
Copyright 2003 by the American Geophysical Union.
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