Atmospheric Semidiurnal Solar Tide Response to Sudden Stratospheric Warmings in the JAGUAR-DAS Whole Neutral Atmosphere Reanalysis (JAWARA) During 2004–2023

Abstract

The migrating semidiurnal solar tide (SW2) originating from the troposphere and stratosphere is a known source of variability in the thermosphere-ionosphere system, and thus is important for accurate space weather prediction. Previous studies have established that the upward-propagation of SW2 into the lower thermosphere can be influenced by Arctic sudden stratospheric warmings (SSWs). In particular, the recent study by Yamazaki and Siddiqui (2024, https://doi.org/10.1029/2023jd040222) showed that the component of SW2 that is antisymmetric about the equator is enhanced. However, their study had a limitation in time resolution, as the satellite data they used required a 60-day integration for determining tides. The present study resolves this issue by using hourly temperature data from the JAGUAR-DAS Whole neutral Atmosphere Reanalysis (JAWARA). SW2 variability in the lower thermosphere is examined for all the boreal winters (December–February) from 2004/2005 to 2022/2023. We show that following the major SSWs in the boreal winters 2005/2006, 2008/2009, 2012/2013, and 2018/2019, the amplitude of SW2 increased and the phase of SW2 became more antisymmetric about the equator. SW2 remained altered during elevated stratopause events. Similar changes occurred during the minor SSW in the boreal winter 2011/2012, which was accompanied by an elevated stratopause event. The changes in SW2 can be well represented by the enhancement of the antisymmetric (2,3) Hough mode of classical tidal theory. The (2,3)-mode amplitude in the lower thermosphere is negatively correlated ($R$ = $-$0.72) with the zonal mean temperature at $80°$N at 50 km, which undergoes cooling during elevated stratopause events.