Study of temperature, wind speed and tides in the upper atmosphere from optical measurements during the 2017-2019 winter's

Abstract.The mesosphere and lower thermosphere are the least studied areas of the earth atmosphere. The reason for this is the lack of monitoring. We have the Fabry-Perot interferometer (FPI) installed in middle latitudes of East Siberia in the geophysical observatory of Institute of Solar-Terrestrial Physics SB RAS (51.8N, 103.1E).  The FPI is a unique instrument and has no analogues in Russia.The FPI with a temporal resolution of about 10–15 minutes observes the natural glow of the night atmosphere of 630.0, 557.7 nm and 843 nm, the characteristic heights of these lines are about 250, 100 and 90 km, respectively. In this study, we use data on the behavior of the zonal, meridional component of wind speed and temperature obtained with 557.7 nm line. We analyze the temperature regime and dynamics of the stratospheric polar vortex according to the data of climatic archive - ERA-interim to get the relationship of SSW and wind regime in MLT.  In this study, we consider winter atmosphere in 2017-2019 over East Siberia, namely the period of sudden stratospheric warming. We compared the evolution of stratospheric warming’s with temporary variations in background wind and temperature and tides in the mesosphere and lower thermosphere. It turned out that the sudden stratospheric warming's made a strong effect in upper layers of the atmosphere. During major stratospheric warming's, the zonal and meridional winds reversed and increase in the semidiurnal and thirdrdiurnal tides. Temperature in MLT dramatic drop followed by an increase during sudden stratospheric warming's. Minor sudden stratospheric warming's had a similar (but much lower in intensity) response in the upper atmosphere.

Acknowledgements. Analysis of stratosphere condition in this work was supported by the Russian Science Foundation, project No. 19-77-00009. Analysis of methosphere condition in ths work was supported by Rusian Foundation for Basic Research project No. 18-05-00594. The measurements were carried out on the instrument of Center for Common Use «Angara» [http://ckp-rf.ru/ckp/ 3056]. The authors gratefully acknowledge the access to the ECMWF ERA-Interim.