The responsibility of the 16-day wave for the SW1- and SW3-tidal-like signatures during 2009 and 2013 sudden stratospheric warming events
Abstract
The winter upper atmosphere is associated with significant global-scale oscillations nearby the period of 12h. The current work resolves the near-12h oscillation, detected in the mesospheric wind by specular meteor radars at Juliusruh and Mohe during sudden stratospheric warming (SSW) 2013 and at Svalbard and Eureka during SSW 2009, into isolated peaks at 11.6h, 12.0h, and 12.4h through high-frequency spectral analyses. To explain the existence of all above near-12h oscillations, the existing studies has to deal with six wave components, namely, the semidiurnal migrating solar and lunar tides (SW2 and M2), two semidiurnal nonmigrating solar tidal modes SW1 and SW3, and the upper or lower sidebands of 16-day planetary wave modulation on SW2. However, through analyzing the coherence of each peak between different longitudinal sectors, our investigations suggest that the simplest solution to explain the peaks entails only four waves in both SSWs: the nonmigrating modes are negligible whereas the sidebands might have been detected at low-frequency resolutions and misinterpreted as the nonmigrating modes.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMSA42A..07H
- Keywords:
-
- 3334 Middle atmosphere dynamics;
- ATMOSPHERIC PROCESSESDE: 3369 Thermospheric dynamics;
- ATMOSPHERIC PROCESSESDE: 3384 Acoustic-gravity waves;
- ATMOSPHERIC PROCESSESDE: 3389 Tides and planetary waves;
- ATMOSPHERIC PROCESSES