A SIMULATION STUDY ON THE DIURNAL VARIATION OF THE SODIUM LAYER IN THE MESOPAUSE REGION
中层顶区Na原子分布昼夜变化的模拟研究

The study of the sodium layer is very important for understanding the mesopause and lower thermosphere region. The atomic Na layer can be a tracer of the atmospheric dynamical process, such as, the tidal wave and gravity waves. Therefore, the observation of Na layer is one of the important method to study the dynamical process in the mesopause region. In this paper, we combine a time-dependent photochemical model, the International Reference Ionosphere model (IRI-95) and a photochemical model of sodium to develop a time-dependent sodium photochemical model. The diurnal variation of the sodium layer is studied by using this model. The results indicate that there is not obvious diurnal variation near the peak of sodium layer. However, at upper and lower parts of the sodium layer, there are diurnal variations. The results are consistent with the observations.