武汉上空中层顶区域潮汐的MF雷达观测

利用武汉中频雷达观测数据进行分析,研究2至3月份武汉上空中层顶潮汐结构及其随高度和时间变化的特性．用Lomb-Scargle周期图方法计算的水平风场动态功率谱表明,武汉上空存在持续的周日潮汐,是中层顶区域风场结构的主要成分．周日潮的平均振幅随高度的增加呈先增后减的趋势．大多数情况下,潮汐谱峰对应的频率与定义值有一定的偏移．周日潮水平扰动速度矢量随时间和高度变化的轨迹表明,经向分量的相位比纬向分量的相位超前,潮汐能量向上传播,对应于向下的相位传播速度．计算得出的经向分量和纬向分量的垂直相速度分别为1．10和1．15 km/h．

MF Radar Observations of Mesospheric Tides Over Wuhan

Data obtained from the MF radar observations in Wuhan have been used to analyzing the tides'structure and variability at the mesospheric altitudes.A dynamic power spectra of the horizontal wind with Lomb-Scargle periodogram illustrates that the diurnal tide is the dominant tidal disturbance and persists almost uninterruptedly in time.The mean amplitudes of the diurnal tidal disturbances show an altitude trend of increasing firstly and decreasing later.The correspond- ing frequency of the tidal spectral peaks often deviates from fixed one.Hodographs of the diurnal tidal wind vector with respect to heights and time indicates that the phase of the meridional compo- nent always leads that of the zonal component and the diurnal tides are upward propagating wave with downward phase progression.The meridional and zonal vertical phase velocities are 1.10 and 1.15 km/h.