Indian Journal of Science and Technology
Year: 2021, Volume: 14, Issue: 11, Pages: 956-963
S G Susanth1*
1 Department of Applied Science and Humanities, Lourdes Matha College of Science and Technology, Trivandrum, 695574, India. Tel.: +91 9746445455
Tel: +91 9746445455
Email: [email protected]
Received Date:08 December 2020, Accepted Date:16 March 2021, Published Date:12 April 2021
Objective: A brief review on the effects of Sudden Stratospheric Warming (SSW) over the equatorial upper atmosphere (80-500 km) obtained using both ground and space-based measurements are presented. The emphasis is given to understand the role of semi-diurnal tidal activity during the SSW. Methods: In order to address this aspect, zonal wind data obtained using meteor wind radar over a tropical station; Trivandrum in India (8.50 N, 77.0 0 E) has been used. Wavelet analysis has been carried out to investigate the role of semi-diurnal and terdiurnal tides during the SSW event of January 2008. For characterizing the event, polar stratospheric temperature (PST) at 10 hPa, as obtained using National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) reanalysis data has been used. In order to characterize the normal behavior, the aforementioned database during December 2007 has been also looked into. Findings: It has been understood that the tropical upper atmosphere exhibits substantial changes in connection with SSW with an increase in the amplitudes of semi diurnal tides of the order of 10-15 m/s in comparison with the normal period. Over the equatorial ionosphere, the changes were observed right from the E region, extending upto the topside F region. It was noticed that the imprints of SSW were not only restricted to the neutral atmospheric parameters such as temperature, density, wind, but also found to have distinct signatures in the electrodynamic processes such as Equatorial electrojet (EEJ), Equatorial Ionization Anomaly (EIA), Equatorial Spread-F (ESF) as well. Novelty: The study, probably for the first time, has conclusively shown that it is not the terdiurnal tides, but the semi-diurnal tides, which are responsible for the SSW induced effects due to its non-linear interaction with planetary waves.
Keywords: Stratospheric sudden warming; Equatorial ionosphere; waves and tides
© 2021 Susanth. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Published By Indian Society for Education and Environment (iSee)
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