GPS as a solar observational instrument: Real‐time estimation of EUV photons flux rate during strong, medium, and weak solar flares

Singh, Talwinder; Hernández‐Pajares, M.; Monte, Enric; García-Rigo, Alberto; Olivares‐Pulido, Germán

doi:10.1002/2015ja021824

Cited by 8 publications

(9 citation statements)

References 16 publications

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“…And the last but not the least, we have an indirect proof that this is a very good approximation for the Solar Flare determination with GNSS: the fulfilment of the first principles model of equations (1) and (2) of Hernández-Pajares et al (2012) based on VTEC rate measurement, when the solar EUV flux rate is derived from such GNSS approach. This is very well correlated with direct solar EUV flux rate measurements from photometers onboard spacecrafts like the SOHO-SEM during one solar cycle (see Hernández-Pajares et al, 2012;Singh et al, 2015).…”

supporting

confidence: 65%

Comments on: Confirming geomagnetic Sfe by means of a solar flare detector based on GNSS

Hernández‐Pajares

Rigo

2020

J. Space Weather Space Clim.

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We report two comments affecting the paper “Curto JJ, Juan JM & Timoté CC, 2019. Confirming geomagnetic Sfe by means of a solar flare detector based on GNSS. J Space Weather Space Clim 9: A42. https://doi.org/10.1051/swsc/2019040”: The first comment is the reporting of two mistakes which distorts the central model used for the measurement and detection of solar flares with GNSS, that might affect as well the most part of results and discussions contained in the paper. And the second comment is the clarification about the authors’ claim of presenting the first work of using the electron content enhancement estimation at the subsolar point for characterizing solar flares with GNSS data, which is not accurate due to the existence of such previous definition and usage.

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supporting

confidence: 65%

Comments on: Confirming geomagnetic Sfe by means of a solar flare detector based on GNSS

Hernández‐Pajares

Rigo

2020

J. Space Weather Space Clim.

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“…As we have seen, under any solar flare which has had an effect on the ionosphere (the most of strong, middle‐intensity, and weak flares of X‐class, M‐class, and C‐class, respectively; Singh et al, ), the VTEC rate in the daylight ionosphere follows a linear relationship on the solar‐zenith angle cosine, being the slope proportional to the EUV solar flux rate.…”

Section: Bgees Algorithmmentioning

confidence: 84%

“…A set of nine solar flares, with different intensities, geoeffectiveness, and values relative to the peak, have been selected to perform a first assessment of BGEES, also in challenging conditions (see first three columns in Table ). They were previously studied in detail by the classical solar‐centered technique GSFLAI in Hernández‐Pajares et al () and Singh et al (). The measurements provided by the same or similar distributed set of permanent ground GPS receivers used in such papers, shown for instance in Figure 2 of Hernández‐Pajares et al (), have been processed with BGEES for studying the solar flares and stellar superflares.…”

Section: Resultsmentioning

confidence: 99%

“…This indicator, presented in Hernández‐Pajares et al () and based on the simple first‐principles model discussed in Wan et al (), is correlated by means of

a

(another way of defining the GNSS Solar Flare Indicator also presented in Hernández‐Pajares et al, ) with the rate of direct EUV measurements. These can be obtained from space‐based photometers during events such as the solar flares (see also Singh et al, ).…”

Section: The Gnss Solar Flare Activity Indicatormentioning

confidence: 99%

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Real‐Time Detection, Location, and Measurement of Geoeffective Stellar Flares From Global Navigation Satellite System Data: New Technique and Case Studies

Hernández‐Pajares

Moreno‐Borràs

2020

Space Weather

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An alternative approach to detect solar flares and quantify the associated extreme ultraviolet (EUV) solar flux rate was introduced in this journal by the authors: Global Navigation Satellite Systems Solar FLAre Indicator (GSFLAI) was founded on the dependence of the sudden electron content increase of the Earth ionosphere versus the angle regarding the flare source, the Sun, given by a simple but accurate first‐principles‐based model. Such overionization is directly measured from the dual‐frequency phase measurements gathered from hundreds of worldwide permanent receivers of the Global Navigation Satellite Systems, GNSS (like the Global Positioning System GPS), working many of them in real time. In this work we generalize GSFLAI for the very challenging scenario of stellar superflares, with a much weaker expected geoeffectiveness on the Earth ionosphere, making it difficult to distinguish its potential footprint regarding conventional ionospheric variability sources. Indeed, we will show that, unlike GSFLAI for solar flares, the new algorithm presented here (Blind GNSS search of Extraterrestrial EUV Sources [BGEES]) is able to detect EUV flares without the previous knowledge of the position of the source, which is also simultaneously estimated, providing an additional quality check of the detection. It will be first assessed with several case studies of solar flares of different intensities analyzed previously with GSFLAI. Finally, by focusing on the night hemisphere to avoid the Sun's larger effect on the ionosphere, the detection and location with BGEES of two recent stellar superflares, Proxima Centauri (18 March 2016, 08:32UT) and NGTS J121939.5‐355557 (1 February 2016, 04:00UT), are presented, strongly suggesting the extension and applicability of the new technique, also in real time.

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“…Several geoeffective solar flares occurred from days 70 to 76, 2015 (11 to 17 March), prior to the St. Patrick's Day storm, and these were detected and notified in real time by the MONITOR system by means of the GNSS solar flare indicator, (GSFLAI; Hernández-Pajares et al, 2012;MonteMoreno and Hernández-Pajares, 2014;Singh et al, 2015) and the sunlit ionosphere sudden TEC enhancement detector (SISTED; García-Rigo, 2012). Figures 18 and 19 show the corresponding plots for the days surrounding the St. Patrick's Day storm.…”

Section: Solar Flaresmentioning

confidence: 99%

MONITOR Ionospheric Network: two case studies on scintillation and electron content variability

et al. 2017

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Abstract. The ESA MONITOR network is composed of high-frequency-sampling global navigation satellite systems (GNSS) receivers deployed mainly at low and high latitudes to study ionosphere variability and jointly with global GNSS data and ionospheric processing software in support of the GNSS and its satellite-based augmentation systems (SBAS) like the European EGNOS. In a recent phase of the project, the network was merged with the CNES/ASECNA network and new receivers were added to complement the latter in the western African sector. This paper summarizes MONITOR, presenting two case studies on scintillations (using almost 2 years of data measurements). The first case occurred during the major St. Patrick's Day geomagnetic storm in 2015. The second case study was performed in the last phase of the project, which was supported by ESA EGNOS Project Office, when we paid special attention to extreme events that might degrade the system performance of the European EG-NOS.

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GPS as a solar observational instrument: Real‐time estimation of EUV photons flux rate during strong, medium, and weak solar flares

Cited by 8 publications

References 16 publications

Comments on: Confirming geomagnetic Sfe by means of a solar flare detector based on GNSS

Comments on: Confirming geomagnetic Sfe by means of a solar flare detector based on GNSS

Real‐Time Detection, Location, and Measurement of Geoeffective Stellar Flares From Global Navigation Satellite System Data: New Technique and Case Studies

MONITOR Ionospheric Network: two case studies on scintillation and electron content variability

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