Observations of field-aligned ionospheric irregularities during quiet and disturbed conditions with EKB radar: first results

Berngardt, O. I.; Золотухина, Н. А.; Oinats, Alexey

doi:10.1186/s40623-015-0302-3

Cited by 19 publications

(16 citation statements)

References 22 publications

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“…To verify the hypothesis, we used the data of 10 mid-latitude coherent decameter radars of the northern hemisphere: nine radars of the SuperDARN network (Super Dual Auroral Radar Network [12]) and the EKB ISTP SB RAS radar [3]. The coordinates of the radars and their fields of view are shown in Fig.2.…”

Section: Experimental Setup and Analysis Techniquesmentioning

confidence: 99%

Attenuation of decameter wavelength sky noise during x-ray solar flares in 2013–2017 based on the observations of midlatitude HF radars

Berngardt

Ruohoniemi

Нишитани

et al. 2018

Journal of Atmospheric and Solar-Terrestrial Physics

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Based on a joint analysis of the data from 10 midlatitude decameter radars the effects are investigated during 80 x-ray flares in the period 2013-2017. For the investigation nine mid-latitude SuperDARN radars of the northern hemisphere (Adak Island West and East radars, Blackstone radar, Christmas Valley East and West radars, Fort Hays East and West radars, Hokaido East radar and Wallops radar) and Ekaterinburg coherent decameter radar of ISTP SB RAS are used. All the radars work in the same 8-20MHz frequency band and have similar hardware and software. During the analysis the temporal dynamics of noise from each of the radar direction and for each flare is investigated separately. As a result, on the basis of about 13000 daily measurements we found a strong anticorrelation between noise power and x-ray flare intensity, that allows to use shortwave sky noise to diagnose the ionospheric effects of x-ray solar flares. It is shown that in 88.3% of cases an attenuation of daytime decameter radio noise is observed during solar flare, correlating with the temporal dynamics of the solar flare. The intensity of decameter noise anticorrelates well (the Pearson correlation coefficient better than -0.5) with the shape of the X-ray flare in the daytime (for solar elevation angle > 0) in 33% of cases, the average Pearson correlation over the daytime is about -0.34. Median regression coefficient between GOES 0.1-0.8nm x-ray intensity and daytime sky-noise attenuation is about −4.4 · 10 4 [dB · m 2 /W t]. Thus, it has been shown that measurements of the decameter sky noise level at midlatitude decameter radars can be used to study the ionospheric absorption of high-frequency waves in the lower ionosphere during x-ray solar flares. This can be explained by the assumption that the most part of decameter sky noise detected by the radars can be interpreted as produced by ground sources at distances of the first propagation hop (˜3000 km).

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Section: Experimental Setup and Analysis Techniquesmentioning

confidence: 99%

Attenuation of decameter wavelength sky noise during x-ray solar flares in 2013–2017 based on the observations of midlatitude HF radars

Berngardt

Ruohoniemi

Нишитани

et al. 2018

Journal of Atmospheric and Solar-Terrestrial Physics

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“…A wide network of radio instruments in the HF range is available with the SuperDARN (Super Dual Auroral Radar Network; Greenwald et al, ; Chisham et al, ) radars and radars close to them in terms of design and software (Berngardt et al, ). The main task of the SuperDARN network is to measure ionospheric convection.…”

Section: Introductionmentioning

confidence: 99%

Global Diagnostics of Ionospheric Absorption During X‐Ray Solar Flares Based on 8‐ to 20‐MHz Noise Measured by Over‐the‐Horizon Radars

et al. 2019

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An analysis of noise attenuation during 80 solar flares between 2013 and 2017 was carried out at frequencies 8–20 MHz using 34 Super Dual Auroral Radar Network radars and the EKB ISTP SB RAS radar. The attenuation was determined on the basis of noise measurements performed by the radars during the intervals between transmitting periods. The location of the primary contributing ground sources of noise was found by consideration of the propagation paths of radar backscatter from the ground. The elevation angle for the ground echoes was determined through a new empirical model. It was used to determine the paths of the noise and the location of its source. The method was particularly well suited for daytime situations, which had to be limited for the most part to only two crossings through the D region. Knowing the radio path was used to determine an equivalent vertical propagation attenuation factor. The change in the noise during solar flares was correlated with solar radiation lines measured by GOES/XRS, GOES/EUVS, SDO/AIA, SDO/EVE, SOHO/SEM, and PROBA2/LYRA instruments. Radiation in the 1 to 8 Å and near 100 Å are shown to be primarily responsible for the increase in the radionoise absorption, and by inference, for an increase in the D and E region density. The data are also shown to be consistent with a radar frequency dependence having a power law with an exponent of −1.6. This study shows that a new data set can be made available to study D and E regions.

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“…YeKB radar is located near Yekaterinburg on the premises of IGph UrB RAS (Institute of Geophysics of the Ural Branch of the Russian Academy of Sciences) Arti observatory (56°N, 58°E). Technical characteristics of the radar are given on the website http://sdrus.iszf.irk.ru/; the basic principles of its operation and data processing techniques are published in [ Berngardt et al ., ; Mager et al ., ]. On the days considered, the YeKB radar operated at a frequency of ~ 11 MHz in the normal scan mode.…”

Section: Data Usedmentioning

confidence: 98%

“…The next long‐duration, continuous BS i structure explicitly connected with the increase in geomagnetic activity, and riometric absorption was detected at 1800–0200 UT on 17–18 March in 2200–0006 MLT sector. The structure was observed at the YeKB radar's minimum ranges R i ~ 400–500 km and should be related to E‐region backscatter [ Berngardt et al ., ]. This structure evolved on the background of low f o E s ≤ 3 MHz at DI373 and high f o E s ~ 5 MHz at SD266.…”

Section: Signals Received By the Yekb Radar And Vertical Sounding Stamentioning

confidence: 99%

Ionospheric effects of St. Patrick's storm over Asian Russia: 17–19 March 2015

et al. 2017

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We have carried out a comprehensive analysis of data from the high‐frequency coherent radar located near Yekaterinburg, ground‐based ionospheric, riometric, and magnetic stations, situated within the radar field of view and in the vicinity of it, as well as from eight radio paths crossing the Asian region of Russia. Using these data, we studied dynamics of ionospheric disturbances over wide longitudinal sector during the first 3 days of the St. Patrick's two‐step severe geomagnetic storm and determined the main mechanisms of their development. We showed that on 17 March during the main and early recovery storm phases, the major contribution to the generation of the ionospheric disturbances had been made by impact ionization by precipitating magnetospheric particles. This had lead to appearance of intense sporadic layers, alternating with intervals of total absorption. The main features of the storm were the large latitude width of the auroral precipitation zone and an expansion of this zone to corrected geomagnetic latitude ~ 45°. We suppose that these peculiarities were due to high variability of interplanetary magnetic field and solar wind impacted on the magnetosphere. The most probable cause of the negative ionospheric disturbance on 18 March might have been a change in the neutral atmosphere composition. Significant differences between measured and simulated values of maximal electron concentration in F2 layer point to the need to improve the existing empirical models of thermosphere, auroral precipitations, and magnetospheric convection in order to use them for modeling of ionospheric parameters during severe geomagnetic storms.

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Observations of field-aligned ionospheric irregularities during quiet and disturbed conditions with EKB radar: first results

Cited by 19 publications

References 22 publications

Attenuation of decameter wavelength sky noise during x-ray solar flares in 2013–2017 based on the observations of midlatitude HF radars

Attenuation of decameter wavelength sky noise during x-ray solar flares in 2013–2017 based on the observations of midlatitude HF radars

Global Diagnostics of Ionospheric Absorption During X‐Ray Solar Flares Based on 8‐ to 20‐MHz Noise Measured by Over‐the‐Horizon Radars

Ionospheric effects of St. Patrick's storm over Asian Russia: 17–19 March 2015

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