03 Feb 2021

03 Feb 2021

Review status: this preprint is currently under review for the journal AMT.

In situ observations of stratospheric HCl using three-mirror integrated cavity output spectroscopy

Jordan Wilkerson1, David S. Sayres2, Jessica B. Smith3, Norton Allen2, Marco Rivero2, Mike Greenberg2, Terry Martin2, and James G. Anderson1,2,3 Jordan Wilkerson et al.
  • 1Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
  • 2Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
  • 3Department of Earth and Planetary Sciences, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA

Abstract. Stratospheric HCl observations are an important diagnostic for the evaluation of catalytic processes that impact the ozone layer. We report here in situ balloon-borne observations of HCl employing an off-axis integrated cavity output spectrometer (ICOS) fitted with a re-injection mirror. The spectrometer has a 90 % response time of 10 s to changes in HCl and a 30 s precision of 26 pptv. The instrument was deployed alongside an ozone instrument in August 2018 on a balloon-borne descent between 20–80 hPa (29–18 km altitude). The observations agreed with nearby satellite measurements (MLS) within 10 % on average. This is the first time that stratospheric measurements of HCl have been made with ICOS and the first time any cavity enhanced HCl instrument has been tested in-flight.

Jordan Wilkerson et al.

Status: open (until 31 Mar 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2021-6', Anonymous Referee #2, 01 Mar 2021 reply
  • CC1: 'Comment on amt-2021-6', L.E.C. Christensen, 01 Mar 2021 reply

Jordan Wilkerson et al.

Data sets

Harvard University Stratospheric Chemistry Experiment data set Jordan Wilkerson

Jordan Wilkerson et al.


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Short summary
The ozone layer in the stratosphere protects life from harmful UV light, but chlorine-based pollution threatens to damage it. We developed an instrument that couples a laser with highly reflective mirrors and advanced electronics to measure an important residue of this pollution: hydrogen chloride. Our instrument has an improved, more modern layout that we successfully tested in flight. This paves the way for future, advanced techniques that seek to evaluate the health of Earth's ozone layer.