VARIABILITY IN THE VERTICAL-DISTRIBUTION OF OZONE MEASURED OVER THUMBA DURING THE 1990 DYANA CAMPAIGN

A rocket campaign was conducted from Thumba (8.5-degrees-N), India, jo intly by India and Russia, to study the vertical distribution of ozone during the International DYANA programme in 1990. Sixteen instrumente d payloads were launched using M-100 rockets to measure the vertical d istribution of ozone at different times of the day and night during th e March-June 1990 period. The ozone density profiles measured during M arch-April show variabilities in the height region below 25 km and abo ve 45 km. The profiles on 10 April show wave-like perturbations with a mplitude increasing with height. The mean ozone density profile for Ma rch-April shows larger values than the May-June mean profile in the al titude region of 30-45 km. The deviations from the mean reference prof ile during March-April are positive, about 15%, while they are negativ e, about 25%, in May-June. Ozone number densities are also found to be larger during the night-time at altitudes above about 50 km. The obse rved increase is larger than the model estimates.