Articles | Volume 9, issue 5
https://doi.org/10.5194/amt-9-2067-2016
https://doi.org/10.5194/amt-9-2067-2016
Research article
 | 
10 May 2016
Research article |  | 10 May 2016

MIPAS database: new HNO3 line parameters at 7.6  µm validated with MIPAS satellite measurements

Agnès Perrin, Jean-Marie Flaud, Marco Ridolfi, Jean Vander Auwera, and Massimo Carlotti

Abstract. Improved line positions and intensities have been generated for the 7.6 µm spectral region of nitric acid. They were obtained relying on a recent reinvestigation of the nitric acid band system at 7.6 µm and comparisons of HNO3 volume mixing ratio profiles retrieved from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) limb emission radiances in the 11 and 7.6 µm domains. This has led to an improved database called MIPAS-2015. Comparisons with available laboratory information (individual line intensities, integrated absorption cross sections, and absorption cross sections) show that MIPAS-2015 provides an improved description of the 7.6 µm region of nitric acid. This study should help to improve HNO3 satellite retrievals by allowing measurements to be performed simultaneously in the 11 and 7.6 µm micro-windows. In particular, it should be useful to analyze existing MIPAS and IASI spectra as well as spectra to be recorded by the forthcoming Infrared Atmospheric Sounding Interferometer – New Generation (IASI-NG) instrument.

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Short summary
Improved line positions and intensities have been generated for the 7.6 µm spectral region of nitric acid, relying on a recent laboratory reinvestigation and comparisons of HNO3 volume mixing ratios retrieved from Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) radiances in the 11 and 7.6 µm regions. The much improved consistency of line intensities in both regions will make it possible to use them simultaneously to retrieve atmospheric HNO3.