MEASUREMENT OF CHLORINE NITRATE IN THE STRATOSPHERE USING THE NU(4) AND NU(5) BANDS

We present laboratory measurements of the absorption cross sections of the vg band (540-580 cm(-1)) of chlorine nitrate made under stratosph eric conditions of temperature and pressure. We use the measured cross sections and observed mid-infrared stratospheric emission spectra to retrieve mid-latitude vertical mixing ratio profiles for both day and night in the altitude range 20-34 km, and compare the results with a s unset profile obtained simultaneously from solar absorption measuremen ts of the v(4) Q branch at 780 cm(-1). The profiles obtained using the se two methods are shown to be in excellent agreement, validating retr ievals using the v(4) band. We also find good agreement in this altitu de range between the observed day/night ratio and the results of a 1-D photochemical model.