Signatures of low latitude–high latitude coupling in the tropical MLT region during sudden stratospheric warming

Abstract

The present paper analyses the variations of daytime mesopause temperature over an equatorial station during polar Stratospheric Sudden Warming (SSW) events, indicating a possible dynamical coupling between the two regions, through the intensification of planetary wave activity. The amplified wave signatures of quasi-16 day period have been seen in the Equatorial Mesopause Temperature (EMT) and Polar Stratospheric Temperature (at 10 hPa) during the course of the SSW. The EMT measurements were made from Trivandrum (8.5°N, 76.5°E), an equatorial station in India and the stratospheric temperatures were obtained from NCEP/NCAR reanalysis. This investigation reveals (1) an overall enhancement and amplified wave activity in the EMT prior to the SSW and (2) propagation of a wave disturbance from equatorial stratosphere to North Pole in about a month. These results are new and reveal some newer aspects of the SSW and its equatorial effects.