Tide Observation And Research On Atmospheric Wind Fields In The Middle Layer And Lower Thermosphere In Wuhan Area

The mesosphere and lower thermosphere(MLT region)is the transition region from the bottom atmosphere to the ionosphere.With the rise of the altitude,the underlying atmosphere is continuously transmitted upward and coupled with the middle and high atmosphere,which increases the complexity of the middle and high-rise atmosphere.Atmospheric tide is an important way of energy transmission in various regions of the atmosphere and its research has been promoting the progress of space physics.The horizontal wind field model plays an important role in the atmospheric tide prediction,among which HWM14 is the latest version of horizontal wind field model.In this dissertation,the wind field observation data of all sky Meteor Radar in Wuhan area are compared with the model of HWM14 and HWM07.In addition,the model forecast data of different latitude areas in China are used to compare the forecast data of Wuhan with that of Beijing and Sanya,which provides the first-hand data for the modification of HWM14 model in Wuhan.Firstly,the MLT area and its detection method are introduced.The development process and current research status of atmospheric horizontal background wind field and atmospheric tide are described,and the important equipment for obtaining observation data: all sky meteor radar is introduced.Atmospheric tides can usually be obtained by extracting the data of atmospheric horizontal wind field collected by meteor radar,and the amplitude and phase of diurnal tides of atmospheric horizontal wind field can be extracted by harmonic fitting function.In 2014-2016 in Beijing(40.3° N,116.2°E),Wuhan(30.5°N,114.6°E)and Sanya(18.3°N,109.6°E),the observation data and data analysis method of all sky meteor radar wind field in three years are described.Secondly,the horizontal wind field in Wuhan is compared with that of HWM14 and HWM07 models.The comparison shows that the monthly mean zonal wind has more easterly circulation and the monthly mean meridional wind has more northward circulation in Wuhan.In the actual observation of the zonal wind,the HWM14 and HWM07 models give better prediction,but the peak height of HWM14 and HWM07 models is higher than the actual observation height.For the diurnal tide,it is found that the predicted amplitude of HWM14 and HWM07 is smaller than the actual observation value and the phase change trend is consistent.For the semidiurnal tide,the peak amplitude shows a periodic annual variation,and the variation trend predicted by the model is in good agreement with the actual observation.Compared with the zonal wind,the phase difference between the predicted value and the observed value of the meridional wind is too large.Finally,the data of Wuhan and different latitudes are compared with the prediction results of HWM07 model.Compared with the HWM07 model,it is found that the Sanya station is quite different from the model.In all the comparison of stations,the zonal wind diurnal tide model is better than the meridional wind diurnal tide model.In the comparison of semidiurnal tide,the Beijing station and Wuhan station have good consistency with the model in the variation trend of semidiurnal tide.The semidiurnal tide of the meridional component of Sanya meteor radar station is slightly worse than that of Beijing station and Wuhan station in the intensity and duration of tide amplitude.In addition,compared with the prediction results of HWM14 model,the latitude component is different from that of the mid latitude Meteor Radar in summer and winter.The difference between the radar measurement results in low latitude and that of HWM14 model is greater than that of the middle latitude area.All meridional wind components in the model predicted diurnal tide and semidiurnal tide are slightly less than the actual observation,and the difference between the prediction of Sanya station HWM14 model is greater than that of Wuhan station and Beijing station,and there are differences between the actual observation and the model prediction in different latitudes.In a word,this dissertation systematically compares the observed atmospheric tides and different HWM models in MLT area of Wuhan,and compares the predicted atmospheric tides of HWM07 and HWM14 models in different latitudes of China with those in Wuhan area,which provides a new idea for studying the variation of atmospheric tides in the upper and lower thermosphere of Wuhan,At the same time,the comparison and reference of HWM14 model prediction are provided,which is helpful to improve the accuracy of model prediction.The tidal observation of the wind field in the mesosphere and the lower thermosphere in Wuhan area lays a foundation for the study of the changes in the middle and upper atmosphere,and is of great significance to the study of space physics.