Summary and Concluding Remarks

Abstract

In this chapter, the main results revealed by the combination of the PANSY radar observation and a long-term simulation using the high-top non-hydrostatic general circulation model, which are closely described in Sections 2 and 3 are summarized. In Section 2, it was shown that, during the first observations made by a complete PANSY radar system (Program of the Antarctic Syowa MST/IS radar) installed at Syowa Station from 16 to 24 March 2015, quasi-12 h period disturbances in the mesosphere at heights of 70 to 80 km were observed. Combining the observational data and numerical simulation outputs, we found that quasi-12 h disturbances are due to large-scale inertia–gravity waves, not to semi-diurnal migrating tides. In Section 3, the first long-term simulation using the high-top non-hydrostatic general circulation model (NICAM) was executed to analyze mesospheric gravity waves. A new finding in Section 3 is that the spectrum of the vertical fluxes of the zonal momentum has an isolated peak at frequencies slightly lower than f at latitudes from 30 to 75° S at a height of 70 km. Section 3 also discusses the physical mechanism for an explanation of the existence of the isolated spectrum peak in the mesosphere. Last, a possible future study is shortly mentioned.