A significant difference was found in the amplitude and polarization spectra of ULF magnetic noise at stations with a base of 120 km during periods of absence of regional thunderstorm activity. A simultaneous analysis of low-frequency data and ionosonde data allowed us to conclude that the difference in the main parameters of the polarization spectrum at two stations is due to the appearance of sporadic Es layers having a nonuniform horizontal intensity distribution with characteristic scales of the order of the base between stations. A difference in the depth of variations in the polarization parameter e was also found during the ionosphere recovery after magnetic storms. It could be related with Es layers, which had not only a nonuniform intensity distribution, but were also located at different altitudes. A difference was found in the frequency scales of the spectral resonance structure during recording of time variations of its fundamental frequencies. Numerical calculations of the parameter e with specifying model Es layers and electron-density profiles corrected at the altitudes of the ionospheric F layer adequately explained the observed difference in the magnetic noise spectra and allowed us to determine the altitudes at which the horizontal ionospheric irregularity existed. The studies were carried out on the basis of records of horizontal magnetic components at Radiophysical Research Institute midlatitude observatories Novaya Zhizn (56° N, 45.74° E) and Staraya Pustyn (55.66° N, 43.63° E, 120 km east of the first reception point).

中文翻译：

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水平电离层非均匀性对地基源超低频磁场空间分布的影响

在没有区域性雷暴活动期间，基地为 120 公里的台站的超低频磁噪声的振幅和极化谱存在显着差异。对低频数据和电离探空仪数据的同时分析使我们得出结论，两个台站偏振光谱主要参数的差异是由于出现具有不均匀水平强度分布的零星 Es 层，其特征尺度为站之间的基站。在磁暴后的电离层恢复过程中还发现了极化参数 e 变化深度的差异。这可能与 Es 层有关，Es 层不仅强度分布不均匀，而且位于不同的高度。在记录其基频的时间变化期间，发现光谱共振结构的频率尺度存在差异。使用指定模型 Es 层和在电离层 F 层高度处校正的电子密度剖面对参数 e 进行数值计算，充分解释了观测到的磁噪声谱差异，并使我们能够确定水平电离层不规则所在的高度。这些研究是根据放射物理研究所中纬度观测站 Novaya Zhizn（北纬 56°，东经 45.74°）和 Staraya Pustyn（北纬 55.66°，东经 43.63°，第一次接收以东 120 公里）的水平磁分量记录进行的观点）。使用指定模型 Es 层和在电离层 F 层高度处校正的电子密度剖面对参数 e 进行数值计算，充分解释了观测到的磁噪声谱差异，并使我们能够确定水平电离层不规则所在的高度。这些研究是根据放射物理研究所中纬度观测站 Novaya Zhizn（北纬 56°，东经 45.74°）和 Staraya Pustyn（北纬 55.66°，东经 43.63°，第一次接收以东 120 公里）的水平磁分量记录进行的观点）。使用指定模型 Es 层和在电离层 F 层高度处校正的电子密度剖面对参数 e 进行数值计算，充分解释了观测到的磁噪声谱差异，并使我们能够确定水平电离层不规则所在的高度。这些研究是根据放射物理研究所中纬度观测站 Novaya Zhizn（北纬 56°，东经 45.74°）和 Staraya Pustyn（北纬 55.66°，东经 43.63°，第一次接收以东 120 公里）的水平磁分量记录进行的观点）。