Abstract The study investigates the gravity waves activity detected in the mesosphere/lower thermosphere (MLT) region (80–120 km) using airglow observations performed by the Spectral Airglow Temperature Imager (SATI) at the Sierra Nevada Observatory (SNO) (37.06∘N, 3.38∘W). In this analysis column emission rates of the OH Meinel (6–2) and O2 Atmospheric (0–1) bands, as well as rotational temperatures derived from these emission rates are employed for the period of 1998–2015. The long time series allows the determination of gravity waves climatology at this site. The gravity wave activity content exhibits an annual variability with a maximum during winter and a faint increase in summer. It was found that gravity waves with periods of less than 3h are more prevalent than those with periods of 3–6h throughout the year, for both column emission rates and rotational temperatures. The gravity wave activity with periods of less than 3h is larger in summer, while gravity waves with period from 3 to 6 h have maximum activity around autumn-winter. The analysis showed that the gravity waves activity surpassed that of the semidiurnal tides, although was still smaller than the planetary wave activity, especially in summer when the planetary waves appear to dominate the dynamics of the MLT region. In general, wave activity is the main source of variability in both OH and O2 airglow emissions with the planetary wave activity being the main driver of the O2 emission variability. However, the rotational temperatures are more affected by seasonal variations, especially the OH rotational temperatures, accounting for more than the 40% of the overall observed variability.

中文翻译：

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来自中纬度北部 SATI 气辉观测的中层大气重力波活动：季节性变化以及与潮汐和类行星波活动的比较

摘要 本研究利用内华达山脉天文台 (SNO) (37.06∘N) 的光谱气辉温度成像仪 (SATI) 进行的气辉观测，研究了在中层/低热层 (MLT) 区域（80-120 公里）中探测到的重力波活动。 , 3.38∘W)。在此分析中，OH 梅涅尔 (6-2) 和 O2 大气 (0-1) 波段的排放率以及从这些排放率得出的旋转温度用于 1998-2015 年期间。长时间序列允许确定该站点的重力波气候学。重力波活动含量呈现年变化，冬季最大，夏季微弱增加。发现周期小于 3 小时的重力波在全年中比周期为 3-6 小时的重力波更为普遍，对于柱发射率和旋转温度。周期小于3h的重力波活动在夏季较大，而周期为3～6h的重力波在秋冬季活动最大。分析表明，重力波活动超过了半日潮，但仍小于行星波活动，特别是在夏季，行星波似乎主导了 MLT 区域的动力学。一般来说，波浪活动是 OH 和 O2 气辉排放变化的主要来源，而行星波浪活动是 O2 排放变化的主要驱动因素。然而，旋转温度受季节变化的影响更大，尤其是 OH 旋转温度，占观察到的整体变化的 40% 以上。