Features of the magnetic disturbance on September 7–8, 2017 by geophysical data

Blagoveshchensky, D. V.; Sergeeva, M. A.; Corona‐Romero, P.

doi:10.1016/j.asr.2019.03.037

Cited by 8 publications

(4 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The increase in the ionization production (rising the f o F 2 ) over Santa Maria is explained by the trapped and azimuthally drifting of energetic particles coming deeper down into the dense neutral atmosphere through the low magnetic field intensity (conserving the second adiabatic invariant) while bouncing between hemispheres. Even though the September 2017 geomagnetic storm was less intense than the August 2018 as indicated by the Dst index, the higher variability detected in the ionospheric parameters during the former storm can be explain by the fact that it consisted of two consecutive magnetic storms separated in time by~13 hr, as well explained by Blagoveshchensky et al (2019).…”

Section: Journal Of Geophysical Research: Space Physicsmentioning

confidence: 98%

On the Sources of the Ionospheric Variability in the South American Magnetic Anomaly During Solar Minimum

Moro

Xu²,

Denardini

et al. 2019

JGR Space Physics

View full text Add to dashboard Cite

We investigate for the first time the variability of the F2 layer critical frequency (foF2), its peak height (hmF2), the thickness parameter B0, and the E region critical frequency (foE) over Santa Maria (29.7° S, 53.7° W, dip angle = −37°), a station located in the central region of the South American Magnetic Anomaly. The selected ionospheric parameters were obtained from ionograms recorded by a recent Digisonde Portable Sounder 4‐D. The time period covers 309 days from 1 September 2017 to 30 August 2018. The diurnal analyses revealed a large day‐to‐day ionospheric variability, with some peculiarities as a strong semiannual pattern superimposed to expected ionospheric behavior. Furthermore, the results show significant differences between the averaged foF2 in December and June solstices, revealing a possible presence of the annual asymmetry. The coefficient of variation (CV) is used as a quantitative description of the variability of each parameter versus time and season. Considering low solar flux and geomagnetically quiet days only, we note that CV is smaller during the daytime and larger during nighttime for all parameters. The least variable ionospheric parameter in our study is foE, while the most variable one is B0. Regarding the F2 layer parameters, we observe that foF2 is much more variable than hmF2. We attribute the observed CV to the neutral atmosphere source over Santa Maria. The ionospheric variability is in general enhanced during geomagnetically disturbed periods. The estimated CV is higher over Santa Maria than Wuhan, China (30.5° N, 114.4° E, dip angle = 46°), a station with no influence of the South American Magnetic Anomaly.

show abstract

Section: Journal Of Geophysical Research: Space Physicsmentioning

confidence: 98%

On the Sources of the Ionospheric Variability in the South American Magnetic Anomaly During Solar Minimum

Moro

Xu²,

Denardini

et al. 2019

JGR Space Physics

View full text Add to dashboard Cite

show abstract

“…In general, the solar and geomagnetic activity conditions for 4–11 September 2017 have been described as complex largely due to the occurrence of multiple solar flares of different classes (e.g., Curto et al, 2018; Mosna et al, 2020; Yasyukevich et al, 2018) and storm‐related activity that led to two consecutive Dst minima separated by about 13 hr on the same day (e.g., Aa et al, 2019; Blagoveshchensky et al, 2019; Lei et al, 2018). Figure 2 shows changes in (a) solar wind velocity, V sw (m/s), and B z component of the interplanetary magnetic field, IMF B z (nT); (b) auroral electrojet, AE (nT) index and SYM‐H (nT) index equivalent to high‐resolution Dst index (Wanliss & Showalter, 2006); and (c) the interplanetary electric field, IEF

= - V_{x} \times B_{z}

(mV/m), during 6–11 September 2017.…”

Section: Data Sourcesmentioning

confidence: 99%

“…Consequently, each storm period may have its particular characteristics and influence on the ionospheric electron density response in high, low, and middle latitude regions (e.g., Yizengaw et al, 2005). Recently, the solar and geophysical conditions during and around 5–14 September 2017 have received considerable attention for a number of reasons including (but not limited to) the period being associated with the following: producing most of the solar flares in Solar Cycle 24 (e.g., Curto et al, 2018; Mosna et al, 2020) with some flare activity leading to significant ionospheric electron density and TEC increase (Li et al, 2018; Mosna et al, 2020; Yasyukevich et al, 2018) in the sunlit longitude regions, geomagnetic storm that led to occurrence of plasma bubbles that were observed over midlatitudes (Aa et al, 2019), existence of long‐duration positive storm effects in some longitudes such as the Asian‐Australian sector (Lei et al, 2018), and the different response in nature of the Earth's magnetosphere and ionosphere to the development and occurrence of the two consecutive storms (e.g., Blagoveshchensky et al, 2019; Jimoh et al, 2019). The interesting nature of this storm period led to a dedicated Special Section Issue in AGU's Journal of Space Weather under the theme “Space Weather Events of 4–10 September 2017”.…”

Section: Introductionmentioning

confidence: 99%

Ionospheric Response at Conjugate Locations During the 7–8 September 2017 Geomagnetic Storm Over the Europe‐African Longitude Sector

et al. 2020

View full text Add to dashboard Cite

This paper focuses on unique aspects of the ionospheric response at conjugate locations over Europe and South Africa during the 7-8 September 2017 geomagnetic storm including the role of the bottomside and topside ionosphere and plasmasphere in influencing electron density changes. Analysis of total electron content (TEC) on 7 September 2017 shows that for a pair of geomagnetically conjugate locations, positive storm effect was observed reaching about 65% when benchmarked on the monthly median TEC variability in the Northern Hemisphere, while the Southern Hemisphere remained within the quiet time variability threshold of ±40%. Over the investigated locations, the Southern Hemisphere midlatitudes showed positive TEC deviations that were in most cases twice the comparative response level in the Northern Hemisphere on the 8 September 2017. During the storm main phase on 8 September 2017, we have obtained an interesting result of ionosonde maximum electron density of the F2 layer and TEC derived from Global Navigation Satellite System (GNSS) observations showing different ionospheric responses over the same midlatitude location in the Northern Hemisphere. In situ electron density measurements from SWARM satellite aided by bottomside ionosonde-derived TEC up to the maximum height of the F2 layer (hmF2) revealed that the bottomside and topside ionosphere as well as plasmasphere electron content contributions to overall GNSS-derived TEC were different in both hemispheres especially for 8 September 2017 during the storm main phase. The differences in hemispheric response at conjugate locations and on a regional scale have been explained in terms of seasonal influence on the background electron density coupled with the presence of large-scale traveling ionospheric disturbances and low-latitude-associated processes. The major highlight of this study is the simultaneous confirmation of most of the previously observed features and their underlying physical mechanisms during geomagnetic storms through a multi-data set examination of hemispheric differences.

show abstract

“…Figure 4 represents the variation in interplanetary parameters and geomagnetic indices during geomagnetic storms that occurred on 07-09 September 2017. The September 2017 space weather events were studied widely because of the complex conditions for the solar and geomagnetic activity, coupled with several solar flares [e.g., Clilverd et al, 2021;Kumar and Kumar, 2020;Liu et al, 2019;Yasyukevich et al, 2018] and storm-related activity that resulted in two consecutive Dst minima separated by approximately 13 hours on the same day [Blagoveshchensky et al, 2019;Lei et al, 2018]. On 08 September 2017, an intense geomagnetic storm (G4) occurred with its first main phase at 01:00 UT, having a minimum SYM-H index of −146 nT and the second main phase during the first main phase recovery, having a minimum SYM-H index of −112 nT at 17:00 UT.…”

Section: Event 3: 07 September To 09 September 2017mentioning

confidence: 99%

Variation of Total Electron Content over Nepal during Geomagnetic Storms: GPS Observations

Silwal,

Gautam,

Poudel

et al. 2023

Russian Journal of Earth Sciences

View full text Add to dashboard Cite

Geomagnetic storms have very profound effects on the Total Electron Content (TEC) of the ionosphere. In order to investigate the equatorial and low-latitude ionospheric response to the geomagnetic storms of varying intensities, a detailed study of vertical TEC (VTEC) variations resulting from Global Positioning System (GPS) data acquired at four GPS stations in Nepal along 80°–90° E longitude and 26°–30° N latitude sector has been carried out in the present work. The results were analyzed with other favorable inducing factors (solar wind parameters and geomagnetic indices) affecting TEC to constrain the causative factor. Positive phases are observed for all the storms studied. During the severe geomagnetic activity, the deviation was ~18 TECU, while it was recorded ~12 TECU and ~8 TECU during moderate and minor geomagnetic activity, respectively. The Detrended Cross-Correlation Analysis (DXA) illustrates that the value of the hourly average VTEC of the BESI station was found to have a strong positive correlation with other stations in all types of storm events, indicating a similar response of all stations towards the space weather events. In addition, the correlation of VTEC with solar wind parameters and geomagnetic indices illustrated that the VTEC shows a strong positive association with solar wind velocity (Vsw) in all three geomagnetic events. In contrast, the correlation of plasma density (Nsw), interplanetary magnetic field (IMF-Bz), the symmetric horizontal component of geomagnetic field (SYM-H), and Geomagnetic Auroral Electrojet (AE) index with VTEC vary with the intensity of the storm. Overall results of the study have revealed the characteristic features of TEC variation over Nepal regions during magnetic storms, which validates earlier research on ionospheric responses to geomagnetic storms and theoretical assumptions.

show abstract

Features of the magnetic disturbance on September 7–8, 2017 by geophysical data

Cited by 8 publications

References 17 publications

On the Sources of the Ionospheric Variability in the South American Magnetic Anomaly During Solar Minimum

On the Sources of the Ionospheric Variability in the South American Magnetic Anomaly During Solar Minimum

Ionospheric Response at Conjugate Locations During the 7–8 September 2017 Geomagnetic Storm Over the Europe‐African Longitude Sector

Variation of Total Electron Content over Nepal during Geomagnetic Storms: GPS Observations

Contact Info

Product

Resources

About