1Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada
2School of Engineering, York University, Toronto, ON, M3J 1P3, Canada
3Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
4Department of Chemistry, Waterloo University, Waterloo, ON, N2L 3G1, Canada
5California Institute of Technology, Pasadena, CA, 91125, USA
6Environment Canada, Downsview, ON, M3H 5T4, Canada
Abstract. Low-resolution atmospheric thermal emission spectra collected by balloon-borne radiometers over the time span of 1990–2002 are used to retrieve vertical profiles of HNO3, CFC-11 and CFC-12 volume mixing ratios between approximately 10 and 35 km altitude. All of the data analyzed have been collected from launches from a Northern Hemisphere mid-latitude site, during late summer, when stratospheric dynamic variability is at a minimum. The retrieval technique incorporates detailed forward modeling of the instrument and the radiative properties of the atmosphere, and obtains a best fit between modeled and measured spectra through a combination of onion-peeling and optimization steps. The retrieved HNO3 profiles are consistent over the 12-year period, and are consistent with recent measurements by the Atmospheric Chemistry Experiment-Fourier transform spectrometer satellite instrument. We therefore find no evidence of long-term changes in the HNO3 summer mid-latitude profile, although the uncertainty of our measurements precludes a conclusive trend analysis.