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Exploring Oxidation in the Remote Free Troposphere: Insights From Atmospheric Tomography (ATom)
- Source :
- Journal of Geophysical Research: Atmospheres. 125
- Publication Year :
- 2020
- Publisher :
- American Geophysical Union (AGU), 2020.
-
Abstract
- Earth's atmosphere oxidizes the greenhouse gas methane and other gases, thus determining their lifetimes and oxidation products. Much of this oxidation occurs in the remote, relatively clean free troposphere above the planetary boundary layer, where the oxidation chemistry is thought to be much simpler and better understood than it is in urban regions or forests. The NASA airborne Atmospheric Tomography study (ATom) was designed to produce cross sections of the detailed atmospheric composition in the remote atmosphere over the Pacific and Atlantic Oceans during four seasons. As part of the extensive ATom data set, measurements of the atmosphere's primary oxidant, hydroxyl (OH), and hydroperoxyl (HO₂) are compared to a photochemical box model to test the oxidation chemistry. Generally, observed and modeled median OH and HO₂ agree to with combined uncertainties at the 2σ confidence level, which is ~±40%. For some seasons, this agreement is within ~±20% below 6 km altitude. While this test finds no significant differences, OH observations increasingly exceeded modeled values at altitudes above 8 km, becoming ~35% greater, which is near the combined uncertainties. Measurement uncertainty and possible unknown measurement errors complicate tests for unknown chemistry or incorrect reaction rate coefficients that would substantially affect the OH and HO₂ abundances. Future analysis of detailed comparisons may yield additional discrepancies that are masked in the median values.
- Subjects :
- Atmospheric Science
010504 meteorology & atmospheric sciences
Planetary boundary layer
Atmospheric sciences
01 natural sciences
Methane
Troposphere
Atmosphere
chemistry.chemical_compound
Geophysics
Altitude
Hydroperoxyl
chemistry
Space and Planetary Science
Atmospheric chemistry
Greenhouse gas
Earth and Planetary Sciences (miscellaneous)
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 21698996 and 2169897X
- Volume :
- 125
- Database :
- OpenAIRE
- Journal :
- Journal of Geophysical Research: Atmospheres
- Accession number :
- edsair.doi...........6807e0f882f1692bd58d52e245c06059