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Observations and Modeling Studies of Solar Eclipse Effects on Oblique High Frequency Radio Propagation
Space Weather ( IF 4.288 ) Pub Date : 2020-09-25 , DOI: 10.1029/2020sw002560
M. L. Moses 1, 2 , L. J. Kordella 1, 3 , G. D. Earle 1 , D. Drob 3 , J. D. Huba 4 , J. M. Ruohoniemi 1 , S. G. Shepherd 5 , V. Sivakumar 1
Affiliation  

The total solar eclipse over the continental United States on 21 August 2017 offered a unique opportunity to study the dependence of the ionospheric density and morphology on incident solar radiation at different local times. The Super Dual Auroral Radar Network (SuperDARN) radars in Christmas Valley, Oregon, and Fort Hays, Kansas, are located slightly southward of the line of totality; they both made measurements of the eclipsed ionosphere. The received power of backscattered signal decreases during the eclipse, and the slant ranges from the westward looking radar beams initially increase and then decrease after totality. The time scales over which these changes occur at each site differ significantly from one another. For Christmas Valley the propagation changes are fairly symmetric in time, with the largest slant ranges and smallest power return occurring coincident with the closest approach of totality to the radar. The Fort Hays signature is less symmetric. In order to investigate the underlying processes governing the ionospheric eclipse response, we use a ray‐tracing code to simulate SuperDARN data in conjunction with different eclipsed ionosphere models. In particular, we quantify the effect of the neutral wind velocity on the simulated data by testing the effect of adding/removing various neutral wind vector components. The results indicate that variations in meridional winds have a greater impact on the modeled ionospheric eclipse response than do variations in zonal winds. The geomagnetic field geometry and the line‐of‐sight angle from each site to the Sun appear to be important factors that influence the ionospheric eclipse response.

中文翻译:

日食对斜向高频无线电传播影响的观测和建模研究

2017年8月21日,美国大陆上的日全食为研究电离层密度和形态对当地不同时间入射太阳辐射的依赖性提供了独特的机会。俄勒冈州圣诞节谷和堪萨斯州海斯堡的超级双极光雷达网(SuperDARN)雷达位于总体线的稍南侧。他们都对蚀过的电离层进行了测量。在日食期间,反向散射信号的接收功率减小,并且从西向看的雷达波束的倾斜范围首先增大,然后在总计之后减小。这些变化在每个站点发生的时间尺度彼此之间存在显着差异。对于圣诞节谷,传播变化在时间上是相当对称的,最大的倾斜范围和最小的功率返回与最接近整体雷达的方法同时发生。福特海斯堡的签名不那么对称。为了研究控制电离层日食响应的基本过程,我们使用射线追踪代码结合不同的电离层电离层模型来模拟SuperDARN数据。特别是,我们通过测试添加/删除各种中性风矢量分量的效果来量化中性风速对模拟数据的影响。结果表明,与纬向风的变化相比,子午风的变化对模拟的电离层日食响应的影响更大。
更新日期:2020-09-25
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