Impacts of Auroral Precipitation on HF Propagation: A Hypothetical Over‐the‐Horizon Radar Case Study

Ruck, J.; Themens, David R.

doi:10.1029/2021sw002901

Cited by 13 publications

(8 citation statements)

References 35 publications

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“…This band is the result of quiet-time soft auroral electron precipitation, which E-CHAIM includes as part of its "storm" model option. Off-great circle deviations caused by auroral ionization were noted by Ruck and Themens (2021) in a case study using ray tracing simulations through an E-CHAIM model ionosphere as well. While outside the scope of this study, future work could address this effect for geomagnetically active times.…”

Section: Discussionmentioning

confidence: 92%

High‐Latitude Off‐Great Circle Propagation Associated With the Solar Terminator

Cameron,

Fiori,

Perry

et al. 2024

Radio Science

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Large‐scale ionospheric gradients associated with the solar terminator can deflect high frequency (HF) radio waves to off‐great circle paths during the morning and evening, negatively impacting technologies reliant on HF radio wave propagation. For example, geolocation algorithms used by scientific and military over‐the‐horizon radars (OTHRs) generally assume on‐great circle propagation, and thus lateral deviations from the great‐circle path can lead to positioning errors. In this study, radio wave propagation is simulated via 3D numerical ray traces though an empirical, high‐latitude model ionosphere initialized for a variety of times of the day and year to explore and quantify high‐latitude off‐great circle propagation associated with the solar terminator. Analysis of these simulations show large scale east‐west ionospheric gradients due to the solar terminator can cause lateral deviations in north‐directed propagation paths exceeding 20° at sunrise and sunset depending on radio wave frequency, though the largest portion of received signal power tends to experience maximum deflections of 5°. An exploration of the dependence of propagation direction on deflection shows that propagation paths parallel to the solar terminator tend to experience the largest deflections. Since the solar terminator at high latitudes is at an angle with respect to north in the winter and summer, propagation paths oriented west or east of north can experience larger deflections than north oriented paths at sunrise and sunset during these times of year. Impacts of these diurnal deflections on the operation of OTHR and scientific radar are discussed, as well as possible strategies for mitigating them.

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Section: Discussionmentioning

confidence: 92%

High‐Latitude Off‐Great Circle Propagation Associated With the Solar Terminator

Cameron,

Fiori,

Perry

et al. 2024

Radio Science

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“…Besides not entirely blocking the F-region, auroral-E echoes are also observed in some of the data and indicate a further source of ionisation that can present significant departures between the modelled propagation with that of the real ionosphere. We have previously demonstrated the sensitivity of OTHR coverage and propagation with aurora, including the occurrence of ducted modes (Ruck & Themens, 2021).…”

Section: Discussionmentioning

confidence: 99%

On the use of SuperDARN Ground Backscatter Measurements for Ionospheric Propagation Model Validation

Ruck,

Themens,

Ponomarenko

et al. 2024

Preprint

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Prior to use in operational systems, it is essential to validate ionospheric models in a manner relevant to their intended application to ensure satisfactory performance. For Over-the-Horizon radars (OTHR) operating in the high-frequency (HF) band (3-30 MHz), the problem of model validation is severe when used in Coordinate Registration (CR) and Frequency Management Systems (FMS). It is imperative that the full error characteristics of models is well understood in these applications due to the critical relationship they impose on system performance. To better understand model performance in the context of OTHR, we introduce an ionospheric model validation technique using the oblique ground backscatter measurements in soundings from the Super Dual Auroral Radar Network (SuperDARN). Analysis is performed in terms of the F-region leading edge (LE) errors and assessment of range-elevation distributions using calibrated interferometer data. This technique is demonstrated by validating the International Reference Ionosphere (IRI) 2016 for January and June in both 2014 and 2018. LE RMS errors of 100-400 km and 400-800 km are observed for winter and summer months, respectively. Evening errors regularly exceeding 1,000 km across all months are identified. Ionosonde driven corrections to the IRI-2016 peak parameters provide improvements of 200-800 km to the LE, with the greatest improvements observed during the nighttime. Diagnostics of echo distributions indicate consistent underestimates in model NmF2 during the daytime hours of June 2014 due to offsets of -8° being observed in modelled elevation angles at 18:00 and 21:00 UT.

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“…The importance of the study is due to the auroral oval influence, significantly on radio technical systems [33,34], including GNSS [35][36][37][38]. The high-frequency over-the-horizon radars suffer from the aurora: the aurora reduces the available range and coverage area twice [34]. The auroral phenomenon causes GNSS scintillations and decreases the GNSS positioning [35,38].…”

Section: Discussionmentioning

confidence: 99%

Auroral Oval Boundary Dynamics on the Nature of Geomagnetic Storm

Edemskiy

Yasyukevich

2022

Remote Sensing

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During emergency events, we could significantly depend on the stable operation of radio communication, navigation, and radars. The ionosphere, especially its auroral regions, significantly influences radio systems, which is why scientists and engineers create systems to monitor these regions. Using data from the global GNSS network, we analyzed the 10 strongest magnetic storms of solar cycle 24: five coronal mass ejection-driven (CME-driven) and five high-speed stream-driven (HSS-driven) storms. The analysis was based on the calculation of the standard deviation of the total electron content (TEC) derivative (rate of TEC index, ROTI). Under all the storms, the ROTI featured similar dynamics: the average ROTI reaches the highest values during the main phase, and the higher the intensity is, the more intense and equatorward the average ROTI registered. The highest cross-correlations are observed with a lag of 1 h, between the IMF z-component Bz and the magnetic latitude where the highest ROTI values appear. The auroral electrojet (SME index) shows the highest impact on the ROTI dynamics. An increase in the space weather indices (in absolute value) is accompanied by a decrease in the latitude where the maximal ROTI occurs. We found that the peculiarities of a storm affect the ROTI dynamics: all the CME-driven storms feature a high cross-correlation (>0.75) between the IMF z-component Bz and the magnetic latitude where the highest ROTI appears, while the HSS-driven storms feature a lower cross-correlation (<0.75) between them. The difference in duration of similar (by maximal values of geomagnetic indices) HSS- and CME-driven storms could produce differences in the highest ROTI values. Correlations show that compared to HSS-driven storms, CME-driven ones more directly impact the ROTI values and locations of regions with a high ROTI.

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Impacts of Auroral Precipitation on HF Propagation: A Hypothetical Over‐the‐Horizon Radar Case Study

Cited by 13 publications

References 35 publications

High‐Latitude Off‐Great Circle Propagation Associated With the Solar Terminator

High‐Latitude Off‐Great Circle Propagation Associated With the Solar Terminator

On the use of SuperDARN Ground Backscatter Measurements for Ionospheric Propagation Model Validation

Auroral Oval Boundary Dynamics on the Nature of Geomagnetic Storm

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