Observation And Analysis Of Thermospheric Vertical Wind In Polar Region Based On Fabry-Perot Interferometer

The thermosphere neutral wind behavior can to some extent reflect the transformation process of energy and momentum in the process of coupling between the thermosphere and the ionosphere.Vertical wind at low and middle latitudes can be ignored,but vertical wind at high latitudes reflects complex physical and chemical processes of the thermosphere.Understanding the dynamic process of thermosphere is of great significance for improving the quality of wireless communication and ensuring the safe operation of close-orbit satellite.In this paper,an all-sky Fabry-Perot interferometer developed by Wuhan University is used to observe the OI630 nm,OI557nm spectrum over the Arctic Yellow River station in the winter of2015 to 2017.The wind field information of the high and low thermosphere is obtained by calculating,and the vertical wind in the polar region is analyzed emphatically.The main results are:The monthly vertical wind in the low thermosphere and high thermosphere winter in the Yellow River Station from 2015 to 2017 is calculated.It is shown that the vertical wind amplitude of the polar thermosphere is small,the vertical wind amplitude of the high thermosphere is larger than the vertical wind amplitude of the low thermosphere and the oscillation is periodic,which is related to the factors such as solar radiation,gravity wave,tide and so on.Over the Yellow River station around midnight in winter,there is usually a vertical upwind.The relationship between vertical wind over the Yellow River station and geomagnetic activity,the(IMF)Bz component of interplanetary magnetic field and the divergence of horizontal wind is studied by statistical method.It is found that the wind velocity value of vertical thermosphere wind increases under strong geomagnetic disturbance.Positive correlation between vertical heat layer wind and Bz and Vertical heat layer wind is not sensitive to horizontal wind divergence.In order to study the behavior of the thermosphere neutral vertical wind above the Yellow River Station during the auroral substorm,the auroral form,the geomagnetic AE,the AL index,the southward component of IMF and the solar wind parameter are measured according to the FPI interferogram.On 19 and 20 December 2015,a geomagnetic quiet event and two auroral substorm events were determined and the line-of-sight wind and the vertical wind for the correspondingperiod of the three events were reversed.The amplitude of the wind of sight during the aurora substorm is higher than that in the calm stage of the geomagnetic field,and the change is more severe.The auroral substorm enhances the motion of the vertical wind,and the response of the vertical wind in the second low thermosphere of the event to the auroral substorm is delayed by about two hours.By analyzing the solar wind parameters and IMF parameters during the three events,the causes of the variation of the vertical wind in the thermosphere of the polar region during the auroral substorm are given.During the auroral substorm,the southward component of the intergalactic magnetic field increases,a large number of auroral particles settle to the ionosphere,the auroral particles precipitate to produce a large amount of Joule heating,and the neutral gas expands and produces updraft.The ion density of low thermosphere is small,and the behavior of vertical wind is dominated by Joule heating.The high thermosphere has a large ion density,and the high-speed moving ions have greater probability of hitting the neutral particles,and then the wind and the moving direction of the neutral particles are changed,and the behavior of the neutral wind is influenced.Joule heating and ion dragging in high thermosphere affect the movement of vertical wind together.Because of the high ion density in high thermosphere,ion dragging plays a more important role.