Advanced meteor radar observations of mesospheric dynamics during 2017 minor SSW over the tropical region

The observations of the advanced meteor radar at the Indian tropical station Tirupati (13.63 degrees N, 79.4 degrees E) have been used to investigate the effects of the 2017 minor Sudden Stratospheric Warming (SSW) on the tropical mesosphere and lower thermosphere (MLT). The episodic minor warmings were observed in February 2017 with the gain of similar to 40 K in the polar stratospheric temperature (PST), followed by a weakening of the eastward wind by 27 m/s. The observations show the large temporal variations in the zonal wind at 75-80 km during the SSW. We report the occurrence of 14-16 day waves in the MLT zonal wind during SSW and the secondary waves (2-7 days) in the meridional wind after SSW. A large enhancement (similar to 30 m/s) is observed in the amplitude of the semi-diurnal tide (SDT) during the SSW. The present results are similar to those observed during the major SSW. Therefore, the present results stress that the studies of minor SSW on the tropical MLT dynamics must be important. (C) 2019 COSPAR. Published by Elsevier Ltd. All rights reserved.