Measurements of CHâOâNOâ in the upper troposphere
Methyl peroxy nitrate (CHâOâNOâ) is a non-acyl peroxy nitrate that is important for photochemistry at low temperatures characteristic of the upper troposphere. We report the first measurements of CHâOâNOâ, which we achieved through a new aircraft inlet configuration, combined with thermal-dissociation laser-induced fluorescence (TD-LIF) detection of NOâ, and describe the accuracy, specificity, and interferences to CHâOâNOâ measurements. CHâOâNOâ is predicted to be a ubiquitous interference to upper-tropospheric NOâ measurements. We describe an experimental strategy for obtaining NOâ observations free of the CHâOâNOâ interference. Using these new methods, we made observations during two recent aircraft campaigns: the Deep Convective Clouds and Chemistry (DC-3) and the Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS) experiments. The CHâOâNOâ measurements we report have a detection limit (S/N = 2) of 15 pptv at 1 min averaging on a background of 200 pptv NOâ and an accuracy of ±40%. Observations are used to constrain the interference of pernitric acid (HOâNOâ) to the CHâOâNOâ measurements, as HOâNOâ partially decomposes (~11%) along with CHâOâNOâ in the heated CHâOâNOâ channel used to detect CHâOâNOâ.
document
https://n2t.org/ark:/85065/d7pn96s3
eng
geoscientificInformation
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publication
2016-01-01T00:00:00Z
publication
2015-02-27T00:00:00Z
Copyright Author(s) 2015. This work is distributed under the Creative Commons Attribution 3.0 License.
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