The 6 September 2017 X‐Class Solar Flares and Their Impacts on the Ionosphere, GNSS, and HF Radio Wave Propagation

Yasyukevich, Yury; Astafyeva, Elvira; Padokhin, A. M.; Ivanova, Vera; Syrovatskii, S.; Podlesnyi, A. V.

doi:10.1029/2018sw001932

Cited by 114 publications

(85 citation statements)

References 46 publications

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“…Powerful solar flares can affect the ionosphere in the dayside regions of the Earth (Afraimovich et al, 2013). For instance, Yasyukevich et al (2018) reported significant flare effects during the 6-10 September interval in the Africa and Eurasia regions. These effects in general last less than the geomagnetic storm influence.…”

Section: Flare Effectsmentioning

confidence: 99%

“…The authors also thank Ilya Zhivetiev from the Institute of Cosmophysical Research and Radio Wave Propagation FEB RAS and Yury Yasyukevich and Anna Mylnikova from the Institute of Solar-Terrestrial Physics SB RAS for providing TayAbsTEC software for this study (http://www.gnss-lab.org/tay-abs-tec; last access 30 June 2018). The dTEC calculations were performed with use of SIMuRG tool(Yasyukevich et al, 2018; https://simurg.iszf.irk.ru; last access: 28 June 2018). The GUVI/TIMED data were downloaded from http://guvitimed.jhuapl.edu (last access 26 August 2018).…”

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confidence: 99%

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Space Weather Events, Hurricanes, and Earthquakes in Mexico in September 2017

et al. 2018

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In the interval of 4–10 September 2017, the Sun presented multiple solar flares from active region AR 2673. There were also coronal mass ejections that interacted with the Earth's magnetosphere. This solar activity produced several space weather events. These events were observed with ground‐based instruments of the Mexican Space Weather Service. The Mexican Array RadioTelescope detected highly perturbed solar transits associated with Type I radio emissions from active regions. The Compact Astronomical Low‐frequency, Low‐cost Instrument for Spectroscopy in Transportable Observatories‐Mexican Array RadioTelescope station detected several radio bursts including a Type III associated with the X8.2 flare on 10 September. The magnetometer detected variations reaching a regional K index of 8.3 during the geomagnetic storm. The ionosphere over Mexico was disturbed by different space weather phenomena with the dominant effects of the geomagnetic storm. We used total electron content data to study latitudinal and longitudinal ionospheric effects in this interval. The cosmic rays monitor detected a Forbush decrease associated also with the geomagnetic storm. This low‐latitude instrumental network in Mexico allowed estimating the regional response to space weather events. Coincidentally with the space weather events referred above, there were also two other types of natural hazards affecting the country at that moment, the hurricane Katia category 2 in the Gulf of Mexico, and two major earthquakes (7 and 19 September 2018). The conjunction of these natural phenomena were close to creating a worst‐case scenario in terms of civil protection reaction.

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Section: Flare Effectsmentioning

confidence: 99%

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confidence: 99%

Space Weather Events, Hurricanes, and Earthquakes in Mexico in September 2017

et al. 2018

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“…In this contribution, the analysis is performed for short baselines in atmosphere quiet days, so that the focus is on the multipath effects under different measurement scenarios. This leads to the second issue to be addressed in this contribution, i.e., determination of the overbounding mean and standard deviations for the between-receiver phase and code noise/biases under different measurement scenarios, which will be used for computation of the representative PLs during the IM.It is noted that during geophysical events like solar flare [22] and magnetic storms [23,24], abnormal ionosphere behaviours may lead to enlarged differential ionospheric errors in the RTK processing. Note that this study is focused on short-baseline RTK positioning in quiet atmosphere conditions, and does not attempt to account for the RTK integrity monitoring under extreme atmospheric conditions.…”

Section: Introductionmentioning

confidence: 99%

Integrity Monitoring for Horizontal RTK Positioning: New Weighting Model and Overbounding CDF in Open-Sky and Suburban Scenarios

et al. 2020

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Integrity monitoring is an essential task for ensuring the safety of positioning services. Under a selected probability of hazardous misleading information, the protection levels (PLs) are computed according to a considered threat model to bound the positioning errors. A warning message is sent to users when the PL exceeds a pre-set alert limit (AL). In the short-baseline real-time relative kinematic positioning, the spatially correlated errors, such as the the orbital errors and the atmospheric delays are significantly reduced. However, the remaining atmospheric residuals and the multipath that are not considered in the observation model could directly bias the positioning results. In this contribution, these biases are analysed with the focus put on the multipath effects in different measurement environments. A new observation weighting model considering both the elevation angle and the signal-to-noise ratios is developed and their impacts on the positional results are investigated. The coefficients of the proposed weighting model are determined for the open-sky and the suburban scenarios with the positional benefits maximised. Next, the overbounding excess-mass cumulative distribution functions (EMCs) are searched on the between-receiver level for the weighted phase and code observations in these two scenarios. Based on the mean and standard deviations of these EMCs, horizontal protection levels (HPLs) are computed for the ambiguity-fixed solutions of real experiments. The HPLs are compared with the horizontal positioning errors (HPEs) and the horizontal ALs (HALs). Using the sequential exclusion algorithm developed for the ambiguity resolution in this contribution, the full ambiguity resolution can be achieved in around 100% and 95% of the time for the open-sky and the suburban scenarios, respectively. The corresponding HPLs of the ambiguity-fixed solutions are at the sub-dm to dm-level for both scenarios, and all the valid ambiguity-fixed HPLs are below a HAL of 0.5 m. For the suburban scenario with more complicated multipath environments, the HPLs increase by considering extra biases to account for multipath under a certain elevation threshold. In complicated multipath environments, when this elevation threshold is set to 30 degrees, the availability of the ambiguity-fixed solutions could decrease to below 50% for applications requiring HAL as low as 0.1 m.

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“…The solar flare is an extreme space weather event, which can induce sudden increase in solar X-ray and extreme ultraviolet irradiance and cause many kinds of sudden ionospheric disturbances (Kumar et al, 2015;Liu et al, 2011;Xiong et al, 2014). Extensive studies have been carried out to investigate the solar flare effects on the ionosphere and the Global Navigation Satellite System (GNSS) applications (Le et al, 2013;Liu et al, 2011;Tsurutani et al, 2009;Wan & Yuan, 2005;Xiong et al, 2014;Xu et al, 2018;Yasyukevich et al, 2018). It can result in an increased measurement noise level and the loss of lock on GNSS signals (Chen et al, 2008;Jakowski et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Investigation of Solar Flares Impact on GPS/BDS/GALILEO Broadcast Ionospheric Models

2019

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The ionosphere is significant to solar‐terrestrial space environment, and the ionospheric delay is considered as one main error source in Global Navigation Satellite System (GNSS). For GNSS single‐frequency users, broadcast ionospheric models (BIMs) play an important role in mitigating the ionospheric delay. Solar activity induces ionospheric disturbances, which can reduce the performance of GNSS. In this study, solar flares impact on Global Positioning System/BeiDou satellite navigation System/Galileo (GPS/BDS/GALILEO) BIMs was investigated in the Asia‐Pacific region. Twelve X‐class and M‐class large solar flares were selected for this study. Total electron content (TEC) derived from selected International GNSS Service and Crustal Movement Observation Network of China (CMONOC) were used to analyze the TEC anomalies and the adaptability of the GPS/BDS/GALILEO BIMs during sample solar flare events. It is verified that very noticeable sudden increase in TEC clearly took place during solar flares. The temporal variation of rate of TEC is more pronounced and rapid with respect to that of TEC. Especially, solar flares impact on the correction accuracy of the GPS/BDS/GALILEO BIMs is significant, as illustrated by a noticeable decrease in relative difference between the observed and modeled TEC values of the GPS/BDS/GALILEO BIMs occurred during the events. Through our investigation, we found that the adaptability of BDS BIM is better than GPS and GALILEO BIMs under solar flare conditions because its coefficients were updated more frequently, while the accuracy of the GALILEO BIM is the highest among current GPS/BDS/GALILEO BIMs in general.

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The 6 September 2017 X‐Class Solar Flares and Their Impacts on the Ionosphere, GNSS, and HF Radio Wave Propagation

Cited by 114 publications

References 46 publications

Space Weather Events, Hurricanes, and Earthquakes in Mexico in September 2017

Space Weather Events, Hurricanes, and Earthquakes in Mexico in September 2017

Integrity Monitoring for Horizontal RTK Positioning: New Weighting Model and Overbounding CDF in Open-Sky and Suburban Scenarios

Investigation of Solar Flares Impact on GPS/BDS/GALILEO Broadcast Ionospheric Models

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