Haloe Antarctic observations in the spring of 1991

HALOE observations of O 3 , CH 4 , HF, H 2 O, NO, NO 2 , and HCℓ collected during the October 1991 Antarctic spring period are reported. The data show a constant CH 4 mixing ratio of about 0.25 ppmv for the altitude range from 65 km down to about 25 km at the position of minimum wind speed in the vortex: i.e., the vortex center, and depressions in pressure versus longitude contours of NO, NO 2 , HF, and HCℓ in this same region. Water vapor, HF, and HCℓ enhancement are also observed in the vortex center region above ∼25 km. Between 10 and 20 km, the expected mixing ratio signatures exist within the vortex, i.e., low ozone and dehydration. The water vapor increased by 50%, and the ozone level doubled inside the vortex between October 11 and 24 in the 15 to 20 km layer. These changes imply a time constant for recovery from ozone hole conditions or 19 and 30 days for O 3 and H 2 O, respectively. The data further show the presence of air inside the vortex between 3 and 30 mb which has mixing ratios characteristic of mid latitudes.