Gravity wave (GW) activities in the upper mesosphere (80–100 km) and their potential sources are investigated using meteor radar observations at King Sejong Station, Antarctica (KSS; 62.22°S, 58.78°W) during recent 14 years (2007–2020). GW activities are estimated by horizontal wind variances of small‐scale GWs (periods <2 h, horizontal wavelength <400 km, or vertical wavelength <3–5 km). The wind variances show clear semiannual variations with maxima at solstices, and annual variations are also seen above z = 90 km. The deseasonalized wind variances at z = 96.8 km have a statistically significant periodicity of ∼11 years that can be associated with solar cycle variations. Three major potential GW sources in the lower atmosphere are examined. Orography is a potential source of GWs in winter and autumn, when the basic‐state wind is westerly from the surface up to the mesosphere. The residual of the nonlinear balance equation (RNBE) at 5 hPa, a diagnostic of the GWs associated with jet stream, is the largest in winter and has a secondary maximum in spring. The correlation between the observed GWs and RNBE is significant in equinoxes, while correlation is low in winter. Deep convection in storm tracks is a potential source in autumn and winter. Secondary GWs generated in the mesosphere can also be observed in the upper mesosphere. Ray‐tracing analysis for airglow images observed at KSS indicates that secondary GWs are mostly generated in winter mesosphere, which may be associated with the breaking of orographic GWs.

中文翻译：

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从南极世宗敬王站流星雷达观测到的中层小尺度重力波的活动（62.22°S，58.78°W）及其潜在来源

最近14年（2007年– 2007年），使用南极世宗国王站（KSS; 62.22°S，58.78°W）的流星雷达观测研究了中高层（80–100 km）的重力波（GW）活动及其潜在源。 2020）。GW活动是通过小型GW的水平风向变化估算的（周期<2 h，水平波长<400 km，垂直波长<3-5 km）。风的方差显示了明显的半年变化，在至高处有最大值，并且在z  = 90 km以上还可以看到年变化。z处的反季节风方差 = 96.8公里的周期具有统计上的显着性，约为11年，可能与太阳周期变化有关。在较低的大气层中，研究了三种主要的潜在GW来源。在冬季和秋季，当基本状态风从地表一直向上吹向中层时，地形学是潜在的GWs来源。在5 hPa时，非线性平衡方程（RNBE）的残差（与喷气流相关的GWs的诊断）在冬季最大，而在春季则为次要最大值。在春分时，观测到的GWs和RNBE之间的相关性很显着，而在冬季，相关性很低。在秋季和冬季，风暴路径中的深对流是一个潜在的来源。在中层中层也可以观察到在中层层中产生的次级GW。