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Simultaneous ground-based and in situ Swarm observations of equatorial F-region irregularities over Jicamarca
Annales Geophysicae ( IF 1.9 ) Pub Date : 2020-10-16 , DOI: 10.5194/angeo-38-1063-2020
Sharon Aol , Stephan Buchert , Edward Jurua , Marco Milla

Abstract. Ionospheric irregularities are a common phenomenon in the low latitude ionosphere. They can be seen in situ as depletions of plasma density, radar plasma plumes or ionogram spread F by ionosondes. In this paper, we compared simultaneous observations of plasma plumes by the Jicamarca unattended long term investigations of the ionosphere and atmosphere (JULIA) radar, ionogram spread F generated from ionosonde observations installed at the Jicamarca Radio Observatory (JRO), and irregularities observed in situ by Swarm, to determine whether Swarm in situ observations can be used as indicators of the presence of plasma plumes and spread-F on the ground. The study covered the years from 2014 to 2018 when all the data-sets were available. Overall, the results showed that Swarm's in situ density fluctuations on magnetic flux tubes passing over (or near) the JRO may be used as indicators of plasma plumes and spread-F over (or near) the observatory. For Swarm and the ground-based observations, a classification procedure was conducted based on the presence or absence of ionospheric irregularity structures. There was a strong consensus between ground-based observations of irregularity structures and Swarm's depth of disturbance of electron density for most passes. Cases, where irregularity structures were observed on the ground with no apparent variation in the in situ electron density or vice versa, suggest that irregularities may either be localized horizontally or restricted to particular height intervals. The results also showed that the Swarm and ground-based observations of ionospheric irregularities had similar local time statistical trends with the highest occurrence obtained between 20:00 and 22:00 LT. Also, similar seasonal patterns of occurrence of in situ and ground-based ionospheric irregularities were observed with the highest percentage occurrence in December Solstice and Equinoxes and low occurrence in June Solstice. The observed seasonal pattern was explained in terms of the pre-reversal enhancement (PRE) of the vertical plasma drift. Initial findings from this research indicate that fluctuations of in situ density observed meridionally along magnetic field lines passing through JRO can be used as an indication of the existence of well-developed plasma plumes.

中文翻译:

对 Jicamarca 上赤道 F 区不规则性的同步地面和原位 Swarm 观测

摘要。电离层不规则是低纬度电离层的常见现象。它们可以在原位被视为等离子体密度的损耗、雷达等离子体羽流或由电离探空仪传播的电离图 F。在本文中,我们比较了 Jicamarca 对电离层和大气 (JULIA) 雷达的无人值守长期调查对等离子体羽流的同步观测、Jicamarca 无线电天文台 (JRO) 安装的电离探空仪观测产生的电离图传播 F 以及原位观测到的不规则性由 Swarm 确定是否可以将 Swarm 原位观测用作指示等离子体羽流和地面扩散 F 的指标。该研究涵盖了从 2014 年到 2018 年所有数据集可用的年份。总体而言,结果表明 Swarm' 通过 JRO 上方(或附近)的磁通量管上的 s 原位密度波动可用作等离子羽流和天文台上方(或附近)扩散 F 的指标。对于 Swarm 和地面观测,根据电离层不规则结构的存在与否进行分类程序。对于大多数通道,不规则结构的地面观测与 Swarm 的电子密度扰动深度之间存在强烈的共识。在地面上观察到不规则结构而原位电子密度没有明显变化的情况下,反之亦然,这表明不规则结构可能是水平定位的,也可能仅限于特定的高度间隔。结果还表明,Swarm 和地面电离层不规则性观测具有相似的本地时间统计趋势,在 LT 20:00 至 22:00 之间获得的最高发生率。此外,还观察到类似的原位和地面电离层不规则性发生的季节性模式,12 月至日和春分发生率最高,而 6 月至日发生率较低。观察到的季节性模式可以用垂直等离子体漂移的预反转增强 (PRE) 来解释。这项研究的初步结果表明,沿穿过 JRO 的磁场线沿子午线观察到的原位密度波动可用作发育良好的等离子体羽流存在的指示。00 和 22:00 LT。此外,还观察到类似的原位和地面电离层不规则性发生的季节性模式,12 月至日和春分发生率最高,而 6 月至日发生率较低。观察到的季节性模式可以用垂直等离子体漂移的预反转增强 (PRE) 来解释。这项研究的初步结果表明,沿穿过 JRO 的磁场线沿子午线观察到的原位密度波动可用作发育良好的等离子体羽流存在的指示。00 和 22:00 LT。此外,还观察到类似的原位和地面电离层不规则性发生的季节性模式,12 月至日和春分的发生率最高,而 6 月至日的发生率较低。观察到的季节性模式可以用垂直等离子体漂移的预反转增强 (PRE) 来解释。这项研究的初步结果表明,沿穿过 JRO 的磁场线沿子午线观察到的原位密度波动可用作发育良好的等离子体羽流存在的指示。观察到的季节性模式可以用垂直等离子体漂移的预反转增强 (PRE) 来解释。这项研究的初步结果表明,沿穿过 JRO 的磁场线沿子午线观察到的原位密度波动可用作发育良好的等离子体羽流存在的指示。观察到的季节性模式可以用垂直等离子体漂移的预反转增强 (PRE) 来解释。这项研究的初步结果表明,沿穿过 JRO 的磁场线沿子午线观察到的原位密度波动可用作发育良好的等离子体羽流存在的指示。
更新日期:2020-10-16
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