Abstract

The dependence of the local annual asymmetry index AI on solar activity has been analyzed based on daily data on the noon values of the F2-layer maximum electron density, NmF2, at the Boulder and Hobart ionospheric stations for 1963–2002. The AI index characterizes the relative difference in the total electron density NmF2 in January and July for a given pair of stations. The weighted-average index of geomagnetic activity ap(τ) at τ = 0.8 was used for the analysis. Low (ap(τ) < 9) and moderate (9 < ap(τ) < 20) geomagnetic activities were identified. It was found for the first time that for low geomagnetic activity, the AI index increases from 0.08 during low solar activity to 0.11–0.12 during moderately high and high solar activity. The AI index for moderate geomagnetic activity is higher (by ΔAI = 0.04–0.05) than that for low geomagnetic activity, which is almost independent of the solar activity level. The AI index for NmF2 median values increases from 0.08 during low solar activity to 0.15–0.16 during high solar activity, which indicates the important role of geomagnetic activity in the dependence of this index on solar activity. A qualitative interpretation of these patterns is given.

中文翻译：

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NmF 2的年度不对称局部指数对太阳活动的依赖性

摘要

根据每日数据，分析了Boulder和Hobart电离层站1963–2002年F 2层最大电子密度NmF 2的中午值，并根据当地年度不对称指数AI对太阳活动的依赖性进行了分析。所述AI指数表征在总电子密度的相对差NMF 2一月和七月对于给定的一对站。地磁活动的加权平均指数ap（τ）在τ= 0.8时用于分析。确定了低（ap（τ）<9）和中等（9 < ap（τ）<20）地磁活动。首次发现，对于低地磁活动，AI指数从低太阳活动时的0.08上升到适度高和高太阳活动时的0.11-0.12。所述AI指数为中等地磁活动性较高（由Δ AI = 0.04-0.05）比用于低地磁活动，这几乎是独立于太阳活动的水平。NmF 2中值的AI指数从低太阳活动时的0.08增加到高太阳活动时的0.15–0.16，这表明地磁活动在该指数对太阳活动的依赖性中起着重要作用。给出了对这些模式的定性解释。