Abstract Digital difference filters were used for the analysis of data of the spectral observations of the rotational temperature and emission intensity of vibrationally excited hydroxyl (OH*) at altitudes 85–90 km at observatories Zvenigorod (56° N, 37° E) for 2004–2016 years and Tory (52° N, 103° E) for 2012–2017. The monthly-average values and standard deviations of mesoscale perturbations of the OH* emission characteristics with periods 0.8–11 h are obtained. These mesoscale perturbations may reflect internal gravity waves (IGWs) in the mesopause region. To filter out mesoscale perturbations, differences between the sequential values of the OH* emission characteristics, averaged over the intervals by duration from 0.5 h to 2 h, were obtained. The average monthly variances of mesoscale perturbations in the OH* rotational temperature obtained at Tory are larger compared to Zvenigorod ones. Average seasonal changes of relative mesoscale variances demonstrate maxima in winter and in summer, with the summer maximum shifted closer to spring months for the Tory station. The reasons for the differences could be different orography and jet streams in the lower and middle atmosphere, also different spectra of IGW horizontal wavelengths due to different geometry of observations at Tory and Zvenigorod.

中文翻译：

---

Tory 和 Zvenigorod 中层顶附近羟基夜光的中尺度变化的多年观测

摘要 2004年Zvenigorod天文台（北纬56度，东经37度）85-90公里处振动激发羟基（OH*）的旋转温度和发射强度光谱观测数据采用数字差分滤波器进行分析。 –2016 年和保守党 (52° N, 103° E) 为 2012-2017。获得了周期为 0.8-11 小时的 OH* 排放特征的中尺度扰动的月平均值和标准偏差。这些中尺度扰动可能反映了中层顶区域的内部重力波 (IGW)。为了滤除中尺度扰动，获得了 OH* 发射特性的连续值之间的差异，在从 0.5 小时到 2 小时的持续时间的间隔内平均。与 Zvenigorod 相比，在 Tory 获得的 OH* 旋转温度中尺度扰动的平均月方差更大。相对中尺度方差的平均季节性变化在冬季和夏季表现出最大值，对于 Tory 站，夏季最大值移至接近春季的月份。造成差异的原因可能是低层和中层大气的地形和急流不同，也可能是由于托里和兹韦尼哥罗德的观测几何形状不同导致 IGW 水平波长的光谱不同。