Understanding the Role of Planetary Waves and Tides in Atmosphere-Ionosphere Coupling Processes During Sudden Stratospheric Warming Events

Abstract:

Recent studies have shown variations in the ionosphere that are linked to changes in the underlying dynamic meteorology during Sudden Stratospheric Warming (SSW) events. In this paper, we present results from ASTRA’s Ionospheric Data Assimilation Four-Dimensional (IDA4D) algorithm to compare and contrast ionospheric response to the 2009 and 2013 SSW events. The ionospheric response in both years was characterized by above normal TECs during the day-time and below average TECs during the night-time. We compared the IDA4D results to highlight significant differences between the ionospheric responses to the 2009 and 2013 SSWs. The ionospheric anomaly during the 2009 SSW event was primarily driven by the non-migrating semidiurnal tide. This is in contrast to the ionospheric variability seen during the 2013 SSW event which exhibited a distinct structure of a migrating semidiurnal tide. These results pose a question as to whether these differences were due to the differences in tides generated in the lower atmosphere or in-situ forcing. We use measurements from the NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) mission to understand the role of various upward atmospheric tides and planetary waves on the ionosphere during the 2009 and 2013 SSW events.