A STUDY OF TROPOPAUSE AND STABLE LAYERS IN LOWER ATMOSPHERE USING THEINDIAN MST RADAR

The mesosphere, stratosphere and troposphere (MST) radar, installed at Gadanki (13.47-degrees-N, 79.18-degrees-E) near Tirupati in Andhra Pr adesh, was used in the ST mode to study the variability of the tropopa use and the stable layers in the atmosphere. For this purpose, the dir ection of the antenna beam was pointed vertically towards zenith, as t he vertically directed radar provides an indication of tropopause. Mea surements with 150 m range resolution were taken for two hours (1430-1 630 IST) for five days in the afternoons of 24-26 Feb. and 23-24 Mar. 1992. Multilayered structures (3-4 layers) were observed below and abo ve the tropopause. The tropopause height was detected from the radioso nde measurements at Madras, a nearby IMD-station. One or two layers we re also always seen in the lower atmosphere in the region of 6.5-8.5 k m height. Within the observation period. these layers were found to va ry in strength (S/N value), but the location remained unchanged though it varied from one day to another. The layer in the lower atmosphere can be turbulent or stable layer and further experiments are needed to verify the nature of the layer.