Increased ionization in the auroral oval leads to the absorption of high‐frequency radio waves in the auroral zone, or auroral absorption. Auroral absorption is typically characterized by global geomagnetic activity indices, such as the Kp index. In this paper the hourly range of the magnetic field (HR) is examined as an alternative to the 3‐hr Kp index for describing the dynamic and localized features of auroral absorption represented by the hourly range of absorption (HRA). Kp, magnetometer, and riometer data were examined for a 3‐year period for stations spread across typical auroral latitudes. A general linear relationship was shown to exist between Kp and LOG₁₀(HRA) for Kp < 4; for Kp ≥ 4 the correlation was weaker. A stronger linear correlation was demonstrated between LOG₁₀(HRA) and LOG₁₀(HR) for HR > 50 nT, characterized by a correlation coefficient of R = 0.63. Increased variability in the relationship between HRA and Kp was attributed to the following factors: the variability of the magnetic field within the 3‐hr window characterized by the Kp index, which was better represented by a 1‐hr HR; the dependence of the Kp index on subauroral magnetic data, which is not subject to the geomagnetic variations typically experienced within the auroral region; and reduced statistics for Kp > 6.

中文翻译：

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基于全球Kp和区域地磁小时范围指数表征极光带吸收

在极光椭圆中增加的电离导致极光区中高频无线电波的吸收或极光吸收。极光吸收通常以整体地磁活动指数（例如Kp指数）为特征。在本文中，以每小时3小时Kp指数作为替代，考察了磁场的小时范围（HR），以描述以小时吸收范围（HRA）表示的极光吸收的动态和局部特征。在3年内检查了跨典型极光纬度的站的Kp，磁力计和辐射计数据。对于Kp <4，表明在Kp和LOG ₁₀（HRA）之间存在一般的线性关系。对于Kp≥4，相关性较弱。LOG ₁₀之间表现出更强的线性相关性（HRA）和LOG ₁₀（HR），HR> 50 nT，其特征在于相关系数R = 0.63。HRA和Kp之间关系的可变性增加归因于以下因素：以Kp指数为特征的3小时窗口内的磁场变化更好地以1小时HR表示；Kp指数对极光下磁数据的依赖性，该数据不受极光区内通常经历的地磁变化的影响；并减少了Kp> 6的统计信息。