[P-EM11] Coupling Processes in the Atmosphere-Ionosphere System

[PEM11-20] Southern hemisphere response to northern hemisphere stratospheric warming events

*Patrick J Espy^1,2, Kristina Shizuka Yamase Skarvang^1,2, Willem van Caspel^1,2, Robert Hibbins^1,2, Andrew Kavanagh³ (1.Norwegian University of Science and Technology, 2.Birkeland Centre for Space Science, 3.The British Antarctic Survey)

Keywords:tide, SSW, interhemispheric

The British Antarctic Survey meteor radar located at Rothera station on the Antarctic Peninsula (68S, 68W), has been used to measure hourly winds from 82 km to 98 km with 2 km vertical resolution from February 2005 to August 2019. The mean winds, as well as the 24- 12- and 8-hour tidal amplitudes were fitted to these winds using a 4-day running window. To remove seasonal effects, an individual, smoothed climatology for each of the tidal components and the mean wind was constructed and used to calculate wind anomalies. A superposed-epoch analysis quantified the behaviour of the wind and tidal amplitude anomalies during the 5, northern hemisphere stratospheric warming events that were accompanied by an elevated stratopause occurring between 2005-2013. The results of that analysis showed that the northern hemisphere events did not cause any significant change in the mean winds or the 24- and 8-hour tidal amplitudes. However, the 12-hour tidal amplitude showed a decrease of between 1 m/s at 84km, and 11 m/s at 92 km, significant between 2 and 8 sigma, 12 to 15 days after the event. Preliminary results using the WACCM-X-SD model show similar southern hemisphere behaviour, and the cause of these anomalies is investigated using a primitive-equation tidal model incorporating mean wind fields derived from the NAVGEM-HA reanalysis. We will present the data, analysis, and model results showing the response of southern hemisphere winds to northern hemisphere stratospheric warming events.