LAUSR

In this investigation, the climatological characteristics of ozone over Irene (25.5o S, 28.1o E) are studied with the aid of both ground-based and satellite observations. The principle aim of this work is therefore to examine the variability of vertical ozone distribution over Irene. Ozonesonde measurements and satellite measurements in the mesosphere-lower thermosphere region from the Microwave Limb Sounder (MLS) onboard the Aura satellite and it measures for the period 2004-2007 are employed in this study. The MLS satellite measurements are collected when it overpasses Irene. The vertical ozone profiles are obtained from ozonesondes and the MLS and are found to be in good agreement from a 15 km altitude and above. Maximum ozone concentration is found in the altitude between 23-27 km. The monthly variation of ozone concentration measured by ozonesondes and MLS show maximum and minimum concentrations during spring and autumn, respectively. During spring, the maximum ozone concentration measured by ozonesonde is 4.5 × 10 12 molecules cm –3 while that measured by the MLS instrument is ~4.1 × 10 12 molecules cm –3 . A difference in the range of 0.4 × 10 12 to 0.8 × 10 12 molecules cm –3 was obtained for all seasons except during winter, when the difference was in the range 0.6 × 10 12 to 0.9 × 10 12 molecules cm –3 .