scholarly journals Co-Seismic Ionospheric Disturbance with Alaska Strike-Slip Mw7.9 Earthquake on 23 January 2018 Monitored by GPS

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 83
Author(s):  
Yongming Zhang ◽  
Xin Liu ◽  
Jinyun Guo ◽  
Kunpeng Shi ◽  
Maosheng Zhou ◽  
...  
Keyword(s):  
Fault Location ◽  
Ionospheric Disturbance ◽  
Near Field ◽  
Singular Spectrum Analysis ◽  
Maximum Amplitude ◽  
Strike Slip ◽  
Ionospheric Disturbances ◽  
Total Electron ◽  
Total Electron Contents ◽  
Alaska Earthquake

The Mw7.9 Alaska earthquake at 09:31:40 UTC on 23 January 2018 occurred as the result of strike slip faulting within the shallow lithosphere of the Pacific plate. Global positioning system (GPS) data were used to calculate the slant total electron contents above the epicenter. The singular spectrum analysis (SSA) method was used to extract detailed ionospheric disturbance information, and to monitor the co-seismic ionospheric disturbances (CIDs) of the Alaska earthquake. The results show that the near-field CIDs were detected 8–12 min after the main shock, and the typical compression-rarefaction wave (N-shaped wave) appeared. The ionospheric disturbances propagate to the southwest at a horizontal velocity of 2.61 km/s within 500 km from the epicenter. The maximum amplitude of CIDs appears about 0.16 TECU (1TECU = 1016 el m−2) near the epicenter, and gradually decreases with the location of sub-ionospheric points (SIPs) far away from the epicenter. The attenuation rate of amplitude slows down as the distance between the SIPs and the epicenter increases. The direction of the CIDs caused by strike-slip faults may be affected by the horizontal direction of fault slip. The propagation characteristics of the ionospheric disturbance in the Alaska earthquake may be related to the complex conditions of focal mechanisms and fault location.

scholarly journals Ionospheric disturbances over East Asia during intense December magnetic storms of 2006 and 2015: similarities and differences

2018 ◽  
Vol 4 (3) ◽  
pp. 28-42 ◽  
Author(s):  
Нина Золотухина ◽  
Nina Zolotukhina ◽  
Владимир Куркин ◽  
Vladimir Kurkin ◽  
Неля Полех ◽  
...  
Keyword(s):  
East Asia ◽  
Critical Frequency ◽  
Geomagnetic Storms ◽  
Initial Conditions ◽  
Ionospheric Disturbance ◽  
Magnetic Storms ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Early Recovery ◽  
Total Electron

Using data from ionosondes, located in East Asia, and total electron content maps, we have made a comparative analysis of ionospheric disturbances associated with the intense geomagnetic storms of December 14–16, 2006 and December 19–22, 2015. These storms had almost equal peak intensities (Dstmin=–162 and –155 nT), but different durations of the main phases (2.5 and 19 hr). At the beginning of both the storms, the region under study was located in the vicinity of the midnight meridian. Ionospheric responses to magnetic storms differed in: i) an increase in the F2-layer critical frequency at subauroral latitudes, caused by an increase in auroral precipitation, during the initial phase of the former storm and the absence of this effect in the latter; (ii) a sharp drop in the critical frequency in the evening hours of the main phase of the latter storm, caused by a shift of the main ionospheric trough to lower latitudes, and the absence of this effect during the former storm; (iii) generation of a short-term positive disturbance observed at subauroral latitudes only in the early recovery phase of the former storm after the negative ionospheric disturbance. During both the storms at middle latitudes there were positive disturbances and wave-like fluctuations of the critical frequency which increased in the vicinity of the dawn meridian. The main causes of the differences between the ionospheric storms are shown to be the differences between the initial conditions of the magnetosphere–ionosphere system and durations of the main phases of magnetic storms.

scholarly journals Assessment and Mitigation of Ionospheric Disturbance Effects on GPS Accuracy and Integrity

2014 ◽  
Vol 67 (3) ◽  
pp. 371-384 ◽  
Author(s):  
Duojie Weng ◽  
Shengyue Ji ◽  
Wu Chen ◽  
Zhizhao Liu
Keyword(s):  
Stochastic Model ◽  
Ionospheric Disturbance ◽  
Equatorial Region ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Dual Frequency ◽  
Statistical Solution ◽  
Positioning Accuracy ◽  
Total Electron ◽  
Gps Accuracy

Ionospheric disturbances affect Global Positioning System (GPS) performance in terms of accuracy and integrity, especially over the equatorial region. During the period of the disturbances, GPS receivers suffer from a high noise level. Not taken into account by the current stochastic model, the ionospheric disturbances degrade GPS positioning accuracy. In addition, non-Gaussian tails are observed in the distribution of the noise during the period of the disturbances; therefore the integrity of GPS can also be affected. This paper develops a statistical solution that is able to mitigate effects of ionospheric disturbances on GPS accuracy and integrity using a commercial dual frequency receiver. The Rate of Total Electron Content (TEC) change Index (ROTI), a parameter derived from the dual frequency receiver, is used to group the levels of ionospheric disturbances. The standard deviations of the pseudorange noise under different groups are evaluated. By incorporating both the ROTI and the satellite elevation, a modified stochastic model is proposed to reduce the effect of the disturbed observation on the positioning accuracy. The performance of the model is evaluated by a test and an inflated sigma for each group is recommended for over-bounding anomalies of observations to protect the user against threats from ionospheric disturbances. This technique, together with results in this paper, can be applied to mitigate the effects of ionospheric disturbances on GPS.

scholarly journals Ionospheric disturbances over East Asia during intense December magnetic storms of 2006 and 2015: similarities and differences

2018 ◽  
Vol 4 (3) ◽  
pp. 39-56
Author(s):  
Нина Золотухина ◽  
Nina Zolotukhina ◽  
Владимир Куркин ◽  
Vladimir Kurkin ◽  
Неля Полех ◽  
...  
Keyword(s):  
East Asia ◽  
Critical Frequency ◽  
Geomagnetic Storms ◽  
Initial Conditions ◽  
Ionospheric Disturbance ◽  
Magnetic Storms ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Early Recovery ◽  
Total Electron

Using data from ionosondes, located in East Asia, and total electron content maps, we have made a comparative analysis of ionospheric disturbances as-sociated with the intense geomagnetic storms of De-cember 14–16, 2006 and December 19–22, 2015. These storms had almost equal peak intensities (Dstmin=–162 and –155 nT), but different durations of the main phases (2.5 and 19 hr). At the beginning of both the storms, the region under study was located in the vicinity of the midnight meridian. Ionospheric re-sponses to magnetic storms differed in: i) an increase in the F2-layer critical frequency at subauroral latitudes, caused by an increase in auroral precipitation, during the initial phase of the former storm and the absence of this effect in the latter; (ii) a sharp drop in the critical frequency in the evening hours of the main phase of the latter storm, caused by a shift of the main ionospheric trough to lower latitudes, and the absence of this effect during the former storm; (iii) generation of a short-term positive disturbance observed at subauroral latitudes only in the early recovery phase of the former storm after the negative ionospheric disturbance. During both the storms at middle latitudes there were positive dis-turbances and wave-like fluctuations of the critical fre-quency which increased in the vicinity of the dawn me-ridian. The main causes of the differences between the ionospheric storms are shown to be the differences be-tween the initial conditions of the magnetosphere-ionosphere system and durations of the main phases of magnetic storms.

scholarly journals Observing wave packets generated by solar terminator in TEC during typhoons

2018 ◽  
Vol 4 (2) ◽  
pp. 33-40
Author(s):  
Илья Едемский ◽  
Ilya Edemsky ◽  
Анна Ясюкевич ◽  
Anna Yasyukevich
Keyword(s):  
Tropical Cyclones ◽  
Wave Packets ◽  
Maximum Amplitude ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Total Electron ◽  
The Pacific ◽  
Typhoon Center ◽  
The Pacific Ocean ◽  
Solar Terminator

In this work, we study ionospheric disturbances excited by the passage of the solar terminator (ST) during tropical cyclones, using total electron content (TEC) data. We have considered 16 intense tropical cyclones (typhoons) that acted in the northwest of the Pacific Ocean near the territory of Japan. We analyze two-dimensional distributions of the number of registered wave packets (WPs) depending on various parameters: local time, WP maximum amplitude, and distance to typhoon. It is shown that in most cases the maximum number of WPs is observed at a distance less than 500–1500 km from the typhoon center and near the time of evening solar terminator passage. For typhoons occurring during autumn periods, the maximum number of WPs is recorded at daytime, and, apparently, is not associated with ST. Distributions of the number of WPs depending on their amplitude have a similar form for all the cases considered, with a maximum of about 0.2 TECU. At the same time, for some typhoons there are a large number of WPs with amplitude up to 0.6–0.8 TECU, which is significantly higher than WP amplitudes under quiet conditions. We briefly discuss the mechanism of possible interaction between ionospheric disturbances caused by two different sources (tropical cyclones and ST passage).

Traveling Ionospheric Disturbances Characteristics during the 2018 Typhoon Maria from GPS Observations

2020 ◽  
Vol 12 (4) ◽  
pp. 746 ◽  
Author(s):  
Yiduo Wen ◽  
Shuanggen Jin
Keyword(s):  
Time Series ◽  
Large Scale ◽  
Ionospheric Disturbance ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Dual Frequency ◽  
Total Electron ◽  
Traveling Ionospheric Disturbances ◽  
Gps Observations

Typhoons often occur and may cause huge loss of life and damage of infrastructures, but they are still difficult to precisely monitor and predict by traditional in-situ measurements. Nowadays, ionospheric disturbances at a large-scale following typhoons can be monitored using ground-based dual-frequency Global Positioning System (GPS) observations. In this paper the responses of ionospheric total electron content (TEC) to Typhoon Maria on 10 July 2018 are studied by using about 150 stations of the GPS network in Taiwan. The results show that two significant ionospheric disturbances on the southwest side of the typhoon eye were found between 10:00 and 12:00 UTC. This was the stage of severe typhoon and the ionospheric disturbances propagated at speeds of 118.09 and 186.17 m/s, respectively. Both traveling ionospheric disturbances reached up to 0.2 TECU and the amplitudes were slightly different. The change in the filtered TEC time series during the typhoon was further analyzed with the azimuth. It can be seen that the TEC disturbance anomalies were primarily concentrated in a range of between −0.2 and 0.2 TECU and mainly located at 135–300° in the azimuth, namely the southwest side of the typhoon eye. The corresponding frequency spectrum of the two TEC time series was about 1.6 mHz, which is consistent with the frequency of gravity waves. Therefore, the upward propagating gravity wave was the main cause of the traveling ionospheric disturbance during Typhoon Maria.

scholarly journals Ionospheric Rayleigh Wave Disturbances Following the 2018 Alaska Earthquake from GPS Observations

2019 ◽  
Vol 11 (8) ◽  
pp. 901 ◽  
Author(s):  
Yuhan Liu ◽  
Shuanggen Jin
Keyword(s):  
Rayleigh Wave ◽  
Acoustic Waves ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Band Pass Filter ◽  
Bottom Pressure ◽  
Pass Filter ◽  
Total Electron ◽  
Gps Observations ◽  
Alaska Earthquake

Big earthquakes often excite the acoustic resonance between the earth’s surface and the lower atmosphere. The perturbations can propagate upward into the ionosphere and trigger ionospheric anomalies detected by dual-frequency GPS observations, but coseismic ionospheric disturbance (CID) directivity and mechanism are not clear. In this paper, the ionospheric response to the Mw = 7.9 Alaska earthquake on 23 January 2018 is investigated from about 100 continuous GPS stations near the epicenter. The fourth-order zero-phase Butterworth band-pass filter with cutoffs of 2.2 mHz and 8 mHz is applied to obtain the ionospheric disturbances. Results show that the CIDs with an amplitude of up to 0.06 total electron content units (TECU) are detected about 10 min after the Alaska earthquake. The CIDs are as a result of the upward propagation acoustic waves triggered by the Rayleigh wave. The propagation velocities of TEC disturbances are around 2.6 km/s, which agree well with the wave propagation speed of 2.7 km/s detected by the bottom pressure records. Furthermore, the ionospheric disturbances following the 2018 Mw = 7.9 Alaska earthquake are inhomogeneous and directional which is rarely discussed. The magnitude of ionospheric disturbances in the western part of the epicenter is more obvious than in the eastern part. This phenomenon also corresponds to the data obtained from the seismographs and bottom pressure records (BPRs) at the eastern and western side of the epicenter.

scholarly journals Observing wave packets generated by solar terminator in TEC during typhoons

2018 ◽  
Vol 4 (2) ◽  
pp. 66-75
Author(s):  
Илья Едемский ◽  
Ilya Edemsky ◽  
Анна Ясюкевич ◽  
Anna Yasyukevich
Keyword(s):  
Tropical Cyclones ◽  
Wave Packets ◽  
Maximum Amplitude ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Total Electron ◽  
The Pacific ◽  
Typhoon Center ◽  
The Pacific Ocean ◽  
Solar Terminator

In this work, we study ionospheric disturbances excited by the passage of the solar terminator (ST) during tropical cyclone periods, using total electron content (TEC) data. We have considered 16 intense tropical cyclones (typhoons) that acted in the northwest of the Pacific Ocean near the territory of Japan. We analyze two-dimensional distributions of the number of registered wave packets (WPs) depending on various parameters: local time, maximum amplitude of packets, and distance to typhoon. It is shown that in most cases the maximum num-ber of WPs is observed at a distance less than 500–1500 km from the typhoon center and near the time of evening solar terminator passage. For typhoons occurring during autumn periods, the maximum number of WPs is recorded at daytime, and, apparently, is not associated with ST. Distributions of the number of WPs depending on their amplitude have a similar form for all the cases considered, with a maximum of about 0.2 TECU. At the same time, for some typhoons there are a large number of WPs with amplitude up to 0.6–0.8 TECU, which is significantly higher than WP amplitudes under quiet conditions. We briefly discuss the mechanism of possible interaction between ionospheric disturbances caused by two different sources (tropical cyclones and ST passage).

scholarly journals Investigation of Low Latitude Spread-F Triggered by Nighttime Medium-Scale Traveling Ionospheric Disturbance

2021 ◽  
Vol 13 (5) ◽  
pp. 945
Author(s):  
Zhongxin Deng ◽  
Rui Wang ◽  
Yi Liu ◽  
Tong Xu ◽  
Zhuangkai Wang ◽  
...  
Keyword(s):  
Ionospheric Disturbance ◽  
Phase Speed ◽  
Morphological Processing ◽  
Wave Number ◽  
Occurrence Rate ◽  
Electron Content ◽  
Low Latitude ◽  
Total Electron ◽  
Medium Scale ◽  
Spread F

In the current study, we investigated the mechanism of medium-scale traveling ionospheric disturbance (MSTID) triggering spread-F in the low latitude ionosphere using ionosonde observation and Global Navigation Satellite System-Total Electron Content (GNSS-TEC) measurement. We use a series of morphological processing techniques applied to ionograms to retrieve the O-wave traces automatically. The maximum entropy method (MEM) was also utilized to obtain the propagation parameters of MSTID. Although it is widely acknowledged that MSTID is normally accompanied by polarization electric fields which can trigger Rayleigh–Taylor (RT) instability and consequently excite spread-F, our statistical analysis of 13 months of MSTID and spread-F occurrence showed that there is an inverse seasonal occurrence rate between MSTID and spread-F. Thus, we assert that only MSTID with certain properties can trigger spread-F occurrence. We also note that the MSTID at night has a high possibility to trigger spread-F. We assume that this tendency is consistent with the fact that the polarization electric field caused by MSTID is generally the main source of post-midnight F-layer instability. Moreover, after thorough investigation over the azimuth, phase speed, main frequency, and wave number over the South America region, we found that the spread-F has a tendency to be triggered by nighttime MSTID, which is generally characterized by larger ΔTEC amplitudes.

scholarly journals Multi-Scale Ionospheric Anomalies Monitoring and Spatio-Temporal Analysis during Intense Storm

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 215
Author(s):  
Na Cheng ◽  
Shuli Song ◽  
Wei Li
Keyword(s):  
Magnetic Storm ◽  
Large Scale ◽  
Temporal Dynamics ◽  
Ionospheric Disturbance ◽  
Ionospheric Scintillation ◽  
Small Scale ◽  
Electron Content ◽  
Total Electron ◽  
Multi Scale ◽  
Intense Storm

The ionosphere is a significant component of the geospace environment. Storm-induced ionospheric anomalies severely affect the performance of Global Navigation Satellite System (GNSS) Positioning, Navigation, and Timing (PNT) and human space activities, e.g., the Earth observation, deep space exploration, and space weather monitoring and prediction. In this study, we present and discuss the multi-scale ionospheric anomalies monitoring over China using the GNSS observations from the Crustal Movement Observation Network of China (CMONOC) during the 2015 St. Patrick’s Day storm. Total Electron Content (TEC), Ionospheric Electron Density (IED), and the ionospheric disturbance index are used to monitor the storm-induced ionospheric anomalies. This study finally reveals the occurrence of the large-scale ionospheric storms and small-scale ionospheric scintillation during the storm. The results show that this magnetic storm was accompanied by a positive phase and a negative phase ionospheric storm. At the beginning of the main phase of the magnetic storm, both TEC and IED were significantly enhanced. There was long-duration depletion in the topside ionospheric TEC during the recovery phase of the storm. This study also reveals the response and variations in regional ionosphere scintillation. The Rate of the TEC Index (ROTI) was exploited to investigate the ionospheric scintillation and compared with the temporal dynamics of vertical TEC. The analysis of the ROTI proved these storm-induced TEC depletions, which suppressed the occurrence of the ionospheric scintillation. To improve the spatial resolution for ionospheric anomalies monitoring, the regional Three-Dimensional (3D) ionospheric model is reconstructed by the Computerized Ionospheric Tomography (CIT) technique. The spatial-temporal dynamics of ionospheric anomalies during the severe geomagnetic storm was reflected in detail. The IED varied with latitude and altitude dramatically; the maximum IED decreased, and the area where IEDs were maximum moved southward.

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