On Perturbations in the Thermal Structure of Tropical Stratosphere & Mesosphere in Winter

Abstract

The M-100 rocket temperature data for 11 winter periods have been examined to evaluate the winter characteristics of stratosphere and mesosphere over Thumba (lat, 8°32'N; long., 76°52'E). The temperature changes in the moddle atmosphere over Thumba associated with the high-latitude stratospheric winter warming (STRATWARM) events have also been studied for 8 cases. At Thumba, the winter is characterized by the annual temperature maximum in the mesosphere and annual temperature minimum in stratosphere. Superimposed on the seasonal changes, warmings in the mesospheric region and cooling in the stratospheric region are observed typically during the high-latitude STRATWARM events. The cooling effect of the STRATWARMs is observed to extend down to about 10-km level in the troposphere over Thumba during the peak of very strong events. Hence almost the whole of the middle atmosphere at this tropical region undergoes thermal changes in association with high-latitude stratospheric warming.