Stratospheric/Mesospheric Warmings over Tropics during Winter & Their Implications for Warming Campaign of 1983-84

Abstract

In the background of conducting stratospheric/mesospheric warming experiment during 1983-84 as a part of the activity of the Indian Middle Atmosphere Programme (IMAP), a detailed investigation has been made for a few past cases of stratospheric/ mesospheric warming events which occurred over the tropics. The rocketsonde temperature data for Thumba (lat., 8.5°N; long., 76.90 E) for 5 winters (1970-71, 1972-73, 1978-79, 1981-82 and 1982-83) have been chosen for the study to illustrate the different features of the warmings. Also, the temperature fields at 25km (~30 mbar) for the polar region (50° N-90° N) for the same period have been studied. The study suggests occurrence of strong temperature perturbations in the tropical stratosphere/mesosphere, and interaction between the polar and the tropical middle atmosphere during the period of warmings. An antiphase relationship between the upper mesosphere and the lower mesosphere/upper stratosphere has been noticed during strong spell of warming events.