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Published November 20, 2008 | Published
Journal Article Open

Atmospheric hydroxyl radical (OH) abundances from ground-based ultraviolet solar spectra: an improved retrieval method

Abstract

The Fourier Transform Ultraviolet Spectrometer (FTUVS) instrument has recorded a long-term data record of the atmospheric column abundance of the hydroxyl radical (OH) using the technique of high resolution solar absorption spectroscopy. We report new efforts in improving the precision of the OH measurements in order to better model the diurnal, seasonal, and interannual variability of odd hydrogen (HOx) chemistry in the stratosphere, which, in turn, will improve our understanding of ozone chemistry and its long-term changes. Until the present, the retrieval method has used a single strong OH absorption line P1(1) in the near-ultraviolet at 32,341 cm−1. We describe a new method that uses an average based on spectral fits to multiple lines weighted by line strength and fitting precision. We have also made a number of improvements in the ability to fit a model to the spectral feature, which substantially reduces the scatter in the measurements of OH abundances.

Additional Information

© 2008 Optical Society of America. Received 5 November 2007; revised 17 September 2008; accepted 19 September 2008; posted 19 September 2008 (Doc. ID 89379); published 19 November 2008. We thank Run-Lie Shia for many valuable discussions on the numerical methods used in this work. We acknowledge the support of the NASA Undergraduate Student Research Program (USRP), the Caltech Summer Undergraduate Research Fellowship (SURF) program, and the NASA Upper Atmosphere Research, Aura Validation, Solar Occultation Satellite Science, and Tropospheric Chemistry Programs. Work at the Jet Propulsion Laboratory, California Institute of Technology, is under contract to the National Aeronautics and Space Administration (NASA).

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August 22, 2023
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October 17, 2023