Infrared spectrometer measurements of nitric (HNO3) and hydrochloric acid (HCl) from Arrival Heights using a Bromem spectrometer

A Bomem infrared Fourier transform spectrometer (FTIR), a high resolution infrared instrument, was used to measure stratospheric nitric (HNO3) and hydrochloric acid (HCl) (measuring spectra at 10 and 3 microns) during the early spring from the time the sun returns until early November at Arrival Heights. The instrument has two detectors (liquid nitrogen cooled) to cover a range of wavelengths from 2 to 10 �m. The bandpasses are analysed for HCl and HNO3 only. Compounds of chlorine and nitrogen in the stratosphere are of particular significance in the ozone depletion question. Raw data are times and recorded interferograms which are Fourier transformed into spectra. The derived data are column amounts of HCl and HNO3.