中层顶波非线性相互作用的甚高频雷达观测研究

The VHF observation and study of nonlinear interaction near mesopause

利用 SOUSY VHF雷达 1 987年 6月 2 2日至 6月 2 9日在挪威 Andoya的观测数据研究了中层顶附近大气风场中行星波、潮汐和惯性重力波的非线性相互作用。首先利用 Lomb- Scargle周期图方法计算了大气纬向风场的功率谱 ,除了行星波和潮汐外 ,在行星波、潮汐的频率和与频率差处有明显的谱峰 ,双谱分析表明这些谱峰是行星波和潮汐相互作用形成的。在 86.4km处 35h行星波、半日潮与 8.9h惯性重力波有较强的非线性耦合 ,半日潮与行星波间有明显的能量传输。半日潮振幅变化的周期为 78h,远大于行星波的周期。 85.2 km处经向风场半日潮振幅的变化周期同样大于与之相互作用的 33h行星波的周期。

Data obtained from SOUSY VHF radar at Andoya,Norway(69°N,16°E)between 22 Jun and 29 Jun 1987 have been used in the study of the nonlinear interactions among planetary waves, tides and inertial gravity waves near the mesopause.In determining the power spectrum of the wind, Lomb Scargle periodogram was used.The planetary waves with periods 120 hours,60hours and 35 hours, diurnal, semidiurnal and terdiurnal tides were found at height 86.4km in the zonal wind.By using the bispectral techniques, the presence of other peaks are confirmed to be involred in the nonlinear interaction between the planetary waves and tidal waves.The energy transimition between planetary wave and tidal wave can be seen after the amplitudes of the triple waves were high pass filtered by using a Butterworth filters.The long termed tidal variability may be resulted from the nonlinear between tidal wave and short period planetaryby wave.