A study on equatorial plasma bubbles over Indian sub-continent using various satellite constellations and techniques

Haridas, Sreekumar; Unnikrishnan, K. P.; Choudhary, R. K.; Bose, Parmita; Rao, P. B.

doi:10.1063/5.0058294

Cited by 3 publications

(4 citation statements)

References 32 publications

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“…A sudden depletion of TEC at line‐of‐sight is referred to as an EPB, a phenomenon that occurs over thousands of kilometers in the meridional direction and over a few hundred kilometers in the zonal directions. Large‐scale ionospheric irregularities are the cause of TEC depletions because they occur with rapid ROT fluctuations and significant enhancements of ROTI simultaneously, and there is a positive correlation between S4 index and ROTI (Alfonsi et al., 2011; Haridas et al., 2021; Liu & Radicella, 2019; Olwendo et al., 2018). Ma and Maruyama (2006) reported that ROTI >0.008 TECU/s indicates ionospheric irregularities of kilometer‐scale size, which can cause amplitude scintillation in signals that pass through the irregularities.…”

Section: Resultsmentioning

confidence: 99%

“…As shown in Figure 7d, two key derived TEC parameters for nocturnal F-region ionospheric irregularities are the rate of TEC (ROT) and the standard deviation of ROT, otherwise known as the rate of TEC index (ROTI) obtained from the Swarm B data. Recently Haridas et al (2021), in their multiconstellation observations of ionospheric irregularities over the near-equatorial stations Changanacherry and Trivandrum (close to Cochin), showed that the parameters associated with the amplitude scintillations such as depletion in TEC, depletion duration, and ROTI could be used to estimate the plasma bubble evolution. A sudden depletion of TEC at line-of-sight is referred to as an EPB, a phenomenon that occurs over thousands of kilometers in the meridional direction and over a few hundred kilometers in the zonal directions.…”

Section: Multi-instrumental Observation Of F-region Irregularities: A...mentioning

confidence: 99%

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Ionospheric Nighttime F‐Region Irregularities During Geomagnetically Quiet Conditions as Observed With 205 MHz VHF Radar at an Equatorial Trough Station, Cochin

et al. 2022

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The VHF radar operating at 205 MHz frequency installed at the Cochin University of Science and Technology (CUSAT) has been configured to probe the nighttime ionospheric field‐aligned irregularities (FAIs) over the near‐equatorial site at Cochin, India during the solar minimum periods. Even though the study period includes the minimum of the 24th and 25th solar cycles, a total of 40 nighttime irregularity events were observed at F‐region heights (150–500 km). Bottom‐type and bottom‐side irregularities were observed in this period, but no large‐scale topside ones at F‐region heights. The nighttime irregularities were most commonly observed at average heights of 200–250 km, accounting for 50% of the total events, and 27.5% of the irregularities preferentially occurred after sunset between 19 and 20 LT. While long‐duration irregularity events were not prominent during this period, irregularities that lasted for less than 50 min were predominant. To check the capability of the 205 MHz VHF radar in observing FAIs, the radar observations were compared with the European Space Agency's ionospheric observation data from the Swarm B satellite. Several derived parameters from the Swarm data set such as electron density (Ne), background Ne (bNe), electron temperature (Te), rate of electron density (ROD), index of ROD (RODI), median vertical total electron content (mVTEC), absolute VTEC (aVTEC), rate of TEC (ROT), ROTI, Bubble Index, and Bubble Probability were utilized for characterizing the ionospheric irregularities. The observation from the Swarm B satellite agrees well with that obtained from the VHF radar.

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Section: Resultsmentioning

confidence: 99%

Section: Multi-instrumental Observation Of F-region Irregularities: A...mentioning

confidence: 99%

Ionospheric Nighttime F‐Region Irregularities During Geomagnetically Quiet Conditions as Observed With 205 MHz VHF Radar at an Equatorial Trough Station, Cochin

et al. 2022

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“…Post-event detection methods provide us with a detailed description of bubble characteristics like bubble depth, bubble occurrence period, and the impact of the bubble on TEC depletion. Numerous techniques have been developed to detect EPBs using data from ground-based instruments, Radar observations [25], ionogram analysis [26], airglow data [10], and Global Navigation Satellite Systems (GNSS) [27][28][29] which include Global Positioning System (GPS), European Global Navigation System (Galileo), Russian Global Navigation Satellite System (GLONASS), Quasi-Zenith Satellite System (QZSS), Satellite-Based Augmentation System (SBAS), Chinese BeiDou Navigation Satellite System (BeiDou) [30,31]. Kelly et al [32] first observed the EPBs using the RADAR data as the plumes or wedges.…”

Section: Introductionmentioning

confidence: 99%

Trailing Equatorial Plasma Bubble Occurrences at a Low-Latitude Location through Multi-GNSS Slant TEC Depletions during the Strong Geomagnetic Storms in the Ascending Phase of the 25th Solar Cycle

Vankadara,

Jamjareegulgarn,

Seemala

et al. 2023

Remote Sensing

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The equatorial plasma bubbles (EPBs) are depleted plasma density regions in the ionosphere occurring during the post-sunset hours, associated with the signal fading and scintillation signatures in the trans-ionospheric radio signals. Severe scintillations may critically affect the performance of dynamic systems relying on global navigation satellite system (GNSS)-based services. Furthermore, the occurrence of scintillations in the equatorial and low latitudes can be triggered or inhibited during space weather events. In the present study, the possible presence of the EPBs during the geomagnetic storm periods under the 25th solar cycle is investigated using the GNSS-derived total electron content (TEC) depletion characteristics at a low-latitude equatorial ionization anomaly location, i.e., KL University, Guntur (Geographic 16°26′N, 80°37′E and dip 22°32′) in India. The detrended TEC with a specific window size is used to capture the characteristic depletion signatures, indicating the possible presence of the EPBs. Moreover, the TEC depletions, amplitude (S4) and phase scintillation (σφ) indices from multi-constellation GNSS signals are probed to verify the vulnerability of the signals towards the scintillation effects over the region. Observations confirm that all GNSS constellations witness TEC depletions between 15:00 UT and 18:00 UT, which is in good agreement with the recorded scintillation indices. We report characteristic depletion depths (22 to 45 TECU) and depletion times (28 to 48 min) across different constellations confirming the triggering of EPBs during the geomagnetic storm event on 23 April 2023. Unlikely, but the other storm events evidently inhibited TEC depletion, confirming suppressed EPBs. The results suggest that TEC depletions from the traditional geodetic GNSS stations could be used to substantiate the EPB characteristics for developing regional as well as global scintillation mitigation strategies.

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“…From previous works, there are various observations to monitor the EPB as well as its initiation, including ionosonde (Wei et al 2021), all-sky airglow imager (Nakata et al 2018), GNSS receivers (Haridas et al 2021), beacon receivers (Watthanasangmechai et al 2016), in situ satellites (Wernik et al 2007), and very high frequency (VHF) radar stations such as in Sanya, China (Li et al 2012), and equatorial atmosphere radar or EAR, Indonesia (Otsuka et al 2009). In general, the EPB structure with various sizes, from meters to hundreds of meters can cause severe scintillation on GNSS signals passing through the EPB phenomenon.…”

Section: Introductionmentioning

confidence: 99%

A study of equatorial plasma bubble structure using VHF radar and GNSS scintillations over the low-latitude regions

et al. 2022

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Ionospheric irregularities can cause detrimental effects on the global navigation satellite system (GNSS) signals, often in the form of rapid fluctuations in both amplitude and phase. Over the low-latitude regions, the equatorial plasma bubble (EPB) frequently arises after sunset, leading to GNSS scintillations since the signals propagate through ionospheric irregularities. The relationship between amplitude ionospheric scintillations (S4 index) on GNSS signals and EPB characteristics is presented. We investigate the geometrical relationship between backscatter echoes associated with the EPB and the multi-constellation and multi-frequency scintillations, specifically, GPS and Galileo constellations with L1/E1 and L5/E5a signals. By analyzing the GNSS scintillations along the GNSS signal paths, the GNSS ionospheric pierce points (IPPs) are mapped with S4 index at different altitudes and projected along the magnetic field line together with the backscatter echoes at the equatorial atmosphere radar (EAR), West Sumatra, Indonesia. Our results are obtained for moderate scintillation cases due to limited data available for this study. The results show the EPB impact ionospheric scintillations. The S4 index on the L5/E5a signal is more susceptible to scintillations than the L1/E1 signal. Moreover, we found a high correlation between EAR backscatter echoes and S4 values on both L1/E1 and L5/E5a at an altitude between 250 and 350 km, indicating that the EPB occurs on the bottomside of the ionosphere.

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A study on equatorial plasma bubbles over Indian sub-continent using various satellite constellations and techniques

Cited by 3 publications

References 32 publications

Ionospheric Nighttime F‐Region Irregularities During Geomagnetically Quiet Conditions as Observed With 205 MHz VHF Radar at an Equatorial Trough Station, Cochin

Ionospheric Nighttime F‐Region Irregularities During Geomagnetically Quiet Conditions as Observed With 205 MHz VHF Radar at an Equatorial Trough Station, Cochin

Trailing Equatorial Plasma Bubble Occurrences at a Low-Latitude Location through Multi-GNSS Slant TEC Depletions during the Strong Geomagnetic Storms in the Ascending Phase of the 25th Solar Cycle

A study of equatorial plasma bubble structure using VHF radar and GNSS scintillations over the low-latitude regions

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