The impact of geomagnetic substorms on radio propagation within the high-frequency (HF) range was analyzed using oblique ionospheric sounding data. These data were obtained from the unique system of radio paths that covers the whole region of the Russian Arctic. The study focused on the effects of two substorms with a twofold difference in intensity. Variations of four radio propagation parameters were studied: the maximum and lowest observed frequencies of the F2 ionospheric layer (F2MOF and F2LOF), and the same frequencies of the sporadic Es layer (EsMOF and EsLOF). Even the weak geomagnetic substorm (AEmax ~ 500 nT) significantly changed the ionosphere state and, consequently, the character of radio propagation at paths. The absorption of signals was more pronounced during a more intense substorm which resulted in loss of information during the transmissions through HF channels. The variations of propagation parameters (ΔMOF and ΔLOF) depend more on the path reflection point location and on the intensity of a substorm. Two substorms with a twofold difference in intensity had similar effects on ΔMOF, except for (a) the more pronounced smoothing of the Main Effect and (b) the higher ΔEsMOF amplitude during the intense substorm. Both issues are explained by more intense particle precipitations during the more intense disturbance.

中文翻译：

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北极斜电离层探测无线电路径上的亚暴表现

使用斜电离层探测数据分析了地磁亚暴对高频 (HF) 范围内无线电传播的影响。这些数据是从覆盖整个俄罗斯北极地区的独特无线电路径系统中获得的。该研究侧重于强度存在两倍差异的两个亚风暴的影响。研究了四个无线电传播参数的变化：F2 电离层（F2MOF 和 F2LOF）的最大和最低观测频率，以及零星 Es 层（EsMOF 和 EsLOF）的相同频率。即使是弱地磁亚暴 (AEmax ~ 500 nT) 也显着改变了电离层状态，从而改变了路径上无线电传播的特征。在更强烈的亚暴期间，信号的吸收更为明显，这导致在通过 HF 信道传输过程中信息丢失。传播参数（ΔMOF和ΔLOF）的变化更多地取决于路径反射点的位置和亚暴的强度。具有两倍强度差异的两个亚暴对 ΔMOF 具有相似的影响，除了 (a) 主效应更明显的平滑和 (b) 在强亚暴期间更高的 ΔEsMOF 振幅。这两个问题都可以通过更强烈的扰动期间更强烈的颗粒沉淀来解释。具有两倍强度差异的两个亚暴对 ΔMOF 具有相似的影响，除了 (a) 主效应更明显的平滑和 (b) 在强亚暴期间更高的 ΔEsMOF 振幅。这两个问题都可以通过更强烈的扰动期间更强烈的颗粒沉淀来解释。具有两倍强度差异的两个亚暴对 ΔMOF 具有相似的影响，除了 (a) 主效应更明显的平滑和 (b) 在强亚暴期间更高的 ΔEsMOF 振幅。这两个问题都可以通过更强烈的扰动期间更强烈的颗粒沉淀来解释。