Comparison of SMILES ClO profiles with satellite, balloon-borne and ground-based measurements

Abstract

Abstract.We evaluate the quality of ClO profiles derived from the Superconducting Submillimeter-Wave LimbEmission Sounder (SMILES) on the International Space Station (ISS). Version 2.1.5 of the level-2 product generated by the National Institute of Information and Communications Technology (NICT) is the subject of this study. Based on sensitivity studies, the systematic error was estimated as 5-10 pptv at the pressure range of 80-20 hPa, 35 pptv at the ClO peak altitude (∼ 4 hPa), and 5-10 pptv at pressures ≤ 0.5 hPa for daytime mid-latitude conditions. For nighttime measurements, a systematic error of 8 pptv was estimated for the ClO peak altitude (∼ 2 hPa). The SMILES NICT v2

Direct estimation of the rate constant of the reaction ClO + HO<sub>2</sub> → HOCl + O<sub>2</sub> from SMILES atmospheric observations

“…Theoretical estimations of the systematic errors are done by a forward-model simulation using a certain reference atmospheric state, and they do not include the actual measurement noise of SMILES observations in order to estimate the maximum impact of each error factor on the bias uncertainties. According to Sagawa et al (2013), the systematic error for ClO is up to about 3 % at 0.28 hPa for the mid-latitude nighttime. In this study, we adopt the systematic error of 3 %, which is derived from the theoretical systematic error analysis of ClO, for all the considered species.…”

“…The systematic error (bias) of SMILES NICT ClO data was estimated in a theoretical manner by Sato et al (2012) and Sagawa et al (2013). Theoretical estimations of the systematic errors are done by a forward-model simulation using a certain reference atmospheric state, and they do not include the actual measurement noise of SMILES observations in order to estimate the maximum impact of each error factor on the bias uncertainties.…”

“…We obtained concentrations of ClO, HO 2 and HOCl from the SMILES NICT (National Institute of Information and Communications Technology) level 2 product version 2.1.5 (Sato et al, 2012;Sagawa et al, 2013;Kasai et al, 2013). VMRs (volume mixing ratios) of the species of interest were retrieved from the spectra observed in the stratosphere and the mesosphere.…”

“…An overview of SMILES is given in Kikuchi et al (2010). Details of the observation of O 3 and ClO are described in Kasai et al (2013), Sato et al (2012), and Sagawa et al (2013).…”

“…The systematic error (bias) of SMILES NICT ClO data 85 was estimated theoretically by Sato et al (2012) and Sagawa et al (2013). These theoretical estimations of the system- HOCl is produced by the Reaction (R1) on in the mesosphere during nighttime, and there is no competing production or destruction reaction.…”