Direct estimation of the rate constant of the reaction ClO + HO2 → HOCl + O2 from SMILES atmospheric observations
Item
Title (Dublin Core)
Direct estimation of the rate constant of the reaction ClO + HO2 → HOCl + O2 from SMILES atmospheric observations
Description (Dublin Core)
Diurnal variations of ClO, HO<sub>2</sub>, and HOCl were simultaneously observed by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) between 12 October 2009 and 21 April 2010. These were the first global observations of the diurnal variation of HOCl in the upper atmosphere. A major reaction for the production of HOCl is ClO + HO<sub>2</sub> → HOCl + O<sub>2</sub> (Reaction (R1)) in extra-polar regions. A model study suggested that in the mesosphere, this is the only reaction influencing the amount of HOCl during the night. The evaluation of the pure reaction period, when only Reaction (R1) occurred in the Cl<sub>y</sub> chemical system, was performed by checking the consistency of the HOCl production rate with the ClO loss rate from SMILES observation data. It turned out that the SMILES data at the pressure level of 0.28 hPa (about 58 km) in the autumn mid-latitude region (20–40°, February–April 2010) during night (between modified local time 18:30 and 04:00) were suitable for the estimation of the rate constant, <i>k</i><sub>1</sub>. The rate constant obtained from SMILES observations was <i>k</i><sub>1</sub>(245 K) = (7.75 ± 0.25) × 10<sup>−12</sup> cm<sup>3</sup> molecule<sup>−1</sup> s<sup>−1</sup>. This result is consistent with results from a laboratory experiment and ab initio calculations for similar low-pressure conditions.
Creator (Dublin Core)
Kuribayashi, K.
Sagawa, H.
Lehmann, R.
Sato, T. O.
Kasai, Y.
Date (Dublin Core)
2018-01-15
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-14-255-2014
https://acp.copernicus.org/articles/14/255/2014/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
