Relevant bibliographies by topics / Equatorial ionospheric

Academic literature on the topic 'Equatorial ionospheric'

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Published: 6 September 2023

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Journal articles on the topic "Equatorial ionospheric"

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Bhattacharyya, Archana. "Equatorial Plasma Bubbles: A Review." Atmosphere 13, no. 10 (October 8, 2022): 1637. http://dx.doi.org/10.3390/atmos13101637.

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The equatorial plasma bubble (EPB) phenomenon is an important component of space weather as the ionospheric irregularities that develop within EPBs can have major detrimental effects on the operation of satellite-based communication and navigation systems. Although the name suggests that EPBs occur in the equatorial ionosphere, the nature of the plasma instability that gives rise to EPBs is such that the bubbles may extend over a large part of the global ionosphere between geomagnetic latitudes of approximately ±15°. The scientific challenge continues to be to understand the day-to-day variability in the occurrence and characteristics of EPBs, such as their latitudinal extent and the development of irregularities within EPBs. In this paper, basic theoretical aspects of the plasma processes involved in the generation of EPBs, associated ionospheric irregularities, and observations of their characteristics using different techniques will be reviewed. Special focus will be given to observations of scintillations produced by the scattering of VHF and higher frequency radio waves while they propagate through ionospheric irregularities associated with EPBs, as these observations have revealed new information about the non-linear development of Rayleigh–Taylor instability in equatorial ionospheric plasma, which is the genesis of EPBs.
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Biktash, L. Z. "Role of the magnetospheric and ionospheric currents in the generation of the equatorial scintillations during geomagnetic storms." Annales Geophysicae 22, no. 9 (September 23, 2004): 3195–202. http://dx.doi.org/10.5194/angeo-22-3195-2004.

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Abstract. The equatorial ionosphere parameters, Kp, Dst, AU and AL indices characterized contribution of different magnetospheric and ionospheric currents to the H-component of geomagnetic field are examined to test the geomagnetic activity effect on the generation of ionospheric irregularities producing VLF scintillations. According to the results of the current statistical studies, one can predict near 70% of scintillations from Aarons' criteria using the Dst index, which mainly depicts the magnetospheric ring current field. To amplify Aarons' criteria or to propose new criteria for predicting scintillation characteristics is the question. In the present phase of the experimental investigations of electron density irregularities in the ionosphere new ways are opened up because observations in the interaction between the solar wind - magnetosphere - ionosphere during magnetic storms have progressed greatly. According to present view, the intensity of the electric fields and currents at the polar regions, as well as the magnetospheric ring current intensity, are strongly dependent on the variations of the interplanetary magnetic field. The magnetospheric ring current cannot directly penetrate the equatorial ionosphere and because of this difficulties emerge in explaining its relation to scintillation activity. On the other hand, the equatorial scintillations can be observed in the absence of the magnetospheric ring current. It is shown that in addition to Aarons' criteria for the prediction of the ionospheric scintillations, models can be used to explain the relationship between the equatorial ionospheric parameters, h'F, foF2, and the equatorial geomagnetic variations with the polar ionosphere currents and the solar wind.
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Onohara, A. N., I. S. Batista, and H. Takahashi. "The ultra-fast Kelvin waves in the equatorial ionosphere: observations and modeling." Annales Geophysicae 31, no. 2 (February 7, 2013): 209–15. http://dx.doi.org/10.5194/angeo-31-209-2013.

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Abstract. The main purpose of this study is to investigate the vertical coupling between the mesosphere and lower thermosphere (MLT) region and the ionosphere through ultra-fast Kelvin (UFK) waves in the equatorial atmosphere. The effect of UFK waves on the ionospheric parameters was estimated using an ionospheric model which calculates electrostatic potential in the E-region and solves coupled electrodynamics of the equatorial ionosphere in the E- and F-regions. The UFK wave was observed in the South American equatorial region during February–March 2005. The MLT wind data obtained by meteor radar at São João do Cariri (7.5° S, 37.5° W) and ionospheric F-layer bottom height (h'F) observed by ionosonde at Fortaleza (3.9° S; 38.4° W) were used in order to calculate the wave characteristics and amplitude of oscillation. The simulation results showed that the combined electrodynamical effect of tides and UFK waves in the MLT region could explain the oscillations observed in the ionospheric parameters.
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Tsunomura, S. "Numerical analysis of global ionospheric current system including the effect of equatorial enhancement." Annales Geophysicae 17, no. 5 (May 31, 1999): 692–706. http://dx.doi.org/10.1007/s00585-999-0692-2.

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Abstract. A modeling method is proposed to derive a two-dimensional ionospheric layer conductivity, which is appropriate to obtain a realistic solution of the polar-originating ionospheric current system including equatorial enhancement. The model can be obtained by modifying the conventional, thin shell conductivity model. It is shown that the modification for one of the non-diagonal terms (Σθφ) in the conductivity tensor near the equatorial region is very important; the term influences the profile of the ionospheric electric field around the equator drastically. The proposed model can reproduce well the results representing the observed electric and magnetic field signatures of geomagnetic sudden commencement. The new model is applied to two factors concerning polar-originating ionospheric current systems. First, the latitudinal profile of the DP2 amplitude in the daytime is examined, changing the canceling rate for the dawn-to-dusk electric field by the region 2 field-aligned current. It is shown that the equatorial enhancement would not appear when the ratio of the total amount of the region 2 field-aligned current to that of region 1 exceeds 0.5. Second, the north-south asymmetry of the magnetic fields in the summer solstice condition of the ionospheric conductivity is examined by calculating the global ionospheric current system covering both hemispheres simultaneously. It is shown that the positive relationship between the magnitudes of high latitude magnetic fields and the conductivity is clearly seen if a voltage generator is given as the source, while the relationship is vague or even reversed for a current generator. The new model, based on the International Reference Ionosphere (IRI) model, can be applied to further investigations in the quantitative analysis of the magnetosphere-ionosphere coupling problems.Key words. Ionosphere (electric fields and currents; equatorial ionosphere; ionosphere-magnetosphere interactions)
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Rishbeth, H. "The equatorial F-layer: progress and puzzles." Annales Geophysicae 18, no. 7 (July 31, 2000): 730–39. http://dx.doi.org/10.1007/s00585-000-0730-6.

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Abstract. This work reviews some aspects of the ionospheric F-layer in the vicinity of the geomagnetic equator. Starting with a historical introduction, brief summaries are given of the physics that makes the equatorial ionosphere so interesting, concentrating on the large-scale structure rather than the smaller-scale instability phenomena. Several individual topics are then discussed, including eclipse effects, the asymmetries of the `equatorial trough', variations with longitude, the semiannual variation, the effects of the global thermospheric circulation, and finally the equatorial neutral thermosphere, including `superrotation' and possible topographic influences.Keyword: Ionosphere (equatorial ionosphere)
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Kobea, A. T., C. Amory-Mazaudier, J. M. Do, H. Lühr, E. Houngninou, J. Vassal, E. Blanc, and J. J. Curto. "Equatorial electrojet as part of the global circuit: a case-study from the IEEY." Annales Geophysicae 16, no. 6 (June 30, 1998): 698–710. http://dx.doi.org/10.1007/s00585-998-0698-1.

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Abstract. Geomagnetic storm-time variations often occur coherently at high latitude and the day-side dip equator where they affect the normal eastward Sq field. This paper presents an analysis of ground magnetic field and ionospheric electrodynamic data related to the geomagnetic storm which occured on 27 May 1993 during the International Equatorial Electrojet Year (IEEY) experiment. This storm-signature analysis on the auroral, mid-latitude and equatorial ground field and ionospheric electrodynamic data leads to the identification of a sensitive response of the equatorial electrojet (EEJ) to large-scale auroral return current: this response consists in a change of the eastward electric field during the pre-sunrise hours (0400-0600 UT) coherently to the high-, mid-, and equatorial-latitude H decrease and the disappearance of the EEJ irregularities between the time-interval 0800-0950 UT. Subsequent to the change in h'F during pre-sunrise hours, the observed foF2 increase revealed an enhancement of the equatorial ionization anomaly (EIA) caused by the high-latitude penetrating electric field. The strengthening of these irregularities attested by the Doppler frequency increase tracks the H component at the equator which undergoes a rapid increase around 0800 UT. The ∆H variations observed at the equator are the sum of the following components: SR, DP, DR, DCF and DT.Keywords. Equatorial electrojet · Magnetosphere-ionosphere interactions · Electric fields and currents · Auroral ionosphere · Ionospheric disturbances
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Le Roux, Y. M., J. Ménard, J. P. Jolivet, and P. J. Davy. "<i>Letter to the Editor:</i> SCIPION, a new flexible ionospheric sounder in Senegal." Annales Geophysicae 16, no. 6 (June 30, 1998): 738–42. http://dx.doi.org/10.1007/s00585-998-0738-x.

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Abstract. SCIPION is a new state of the art digital sounder that has been devoloped by France Telecom-CNET for ionospheric monitoring and research. Extensive data processing using DSP technology has resulted in a low power, low cost and full featured system for both vertical and oblique soundings. A SCIPION system is in the process of being installed in Dakar, Senegal, to study HF propagation in the sub-equatorial ionosphere. However, preliminary results have still been obtained during experiments wit a prototype system. In this paper, the system is described and some illustrative examples of its capabilities are shown.Keywords. Ionosphere (Equatorial ionosphere, Instruments and Techniques) &amp;#x22C5 Radio science (ionospheric propagation).
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Sahai, Y., P. R. Fagundes, J. R. Abalde, A. A. Pimenta, J. A. Bittencourt, Y. Otsuka, and V. H. Rios. "Generation of large-scale equatorial F-region plasma depletions during lowrange spread-F season." Annales Geophysicae 22, no. 1 (January 1, 2004): 15–23. http://dx.doi.org/10.5194/angeo-22-15-2004.

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Abstract. All-sky imaging observations of the F-region OI 630nm nightglow emission allow us to visualize large-scale equatorial plasma depletions, generally known as trans-equatorial plasma bubbles. Strong range type spread-F is the radio signature of these (magnetically) north-south aligned plasma depletions. An extensive database of the OI 630nm emission all-sky imaging observations has been obtained at Cachoeira Paulista (22.7°S, 45.0°W; dip latitude ∼16°S), Brazil, between the years 1987 and 2000. An analysis of these observations revealed that relatively few large-scale ionospheric plasma depletions occur during the months of May to August (southern winter, June solstice) in the Brazilian sector. Of the few that are observed during these months, some occur in association with geomagnetic storms and some do not. In this paper, a detailed analysis of the events when large-scale ionospheric plasma depletions were initiated and evolved during the June solstice periods are presented and discussed.Key words. Atmospheric composition and chemistry (airglow and aurora). Ionosphere (equatorial ionosphere; ionospheric irregularities)
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Wang, Hai-Ning, Qing-Lin Zhu, Xiang Dong, Dong-Sheng Sheng, Yong-Feng Zhi, Chen Zhou, and Bin Xu. "A Novel Technique for High-Precision Ionospheric VTEC Estimation and Prediction at the Equatorial Ionization Anomaly Region: A Case Study over Haikou Station." Remote Sensing 15, no. 13 (July 4, 2023): 3394. http://dx.doi.org/10.3390/rs15133394.

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This paper introduces a novel technique that uses observation data from GNSS to estimate the ionospheric vertical total electron content (VTEC) using the Kriging–Kalman method. The technique provides a method to validate the accuracy of the Ionospheric VTEC analysis within the Equatorial Ionization anomaly region. The technique developed uses GNSS VTEC alongside solar parameters, such as solar radio flux (F10.7 cm), Disturbance Storm Time (Dst) and other data, and Long Short Term Memory (LSTM) Networks to predict the occurrence time of the ionospheric equatorial anomaly and ionospheric VTEC changes. The LSTM method was applied to GNSS data from Haikou Station. A comparison of this technique with the neural network (NN) model and International Reference Ionosphere model shows that the LSTM outperforms all of them at VTEC estimation and prediction. The results, which are based on the root mean square error (RMSE) between GNSS VTEC and GIM VTEC outside the equatorial anomaly region, was 1.42 TECU, and the results of GNSS VTEC and VTEC from Beidou geostationary orbit satellite, which lies inside the equatorial ionization anomaly region, was 1.92 TECU. The method developed can be used in VTEC prediction and estimation in real time space operations.
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Kulyamin, Dmitry V., Pavel A. Ostanin, and Valentin P. Dymnikov. "INM-IM: INM RAS Earth ionosphere F region dynamical model." Russian Journal of Numerical Analysis and Mathematical Modelling 37, no. 6 (December 1, 2022): 349–62. http://dx.doi.org/10.1515/rnam-2022-0028.

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Abstract A new INM RAS global dynamical model of Earth’s ionosphere F region (100–500 km), which takes into account plasma-chemical processes, ambipolar diffusion, and advective ion transport due to electromagnetic drifts and neutral wind is presented. The model includes parameterizations of polar electric fields induced by magnetospheric convection and simplified equatorial drifts considerations. The focus of the paper is directed on the description of specific methods developed and utilized in the ionospheric model. Key processes responsible for the formation of global ionospheric features are outlined and their representation in the model is evaluated. The main global ionospheric characteristic features, such as seasonal and diurnal cycles, the equatorial ionization anomaly (EIA), polar ionization caps and the main trough have been adequately reproduced based on this model.
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Dissertations / Theses on the topic "Equatorial ionospheric"

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Chapagain, Narayan P. "Dynamics of Equatorial Spread F Using Ground-Based Optical and Radar Measurements." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/897.

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The Earth's equatorial ionosphere most often shows the occurrence of large plasma density and velocity fluctuations with a broad range of scale sizes and amplitudes. These night time ionospheric irregularities in the F-region are commonly referred to as equatorial spread F (ESF) or plasma bubbles (EPBs). This dissertation focuses on analysis of ground-based optical and radar measurements to investigate the development and dynamics of ESF, which can significantly disrupt radio communication and GPS navigation systems. OI (630.0 nm) airglow image data were obtained by the Utah State University all-sky CCD camera, primarily during the equinox period, from three different longitudinal sectors under similar solar flux conditions: Christmas Island in the Central Pacific Ocean, Ascension Island in South Atlantic, and Brasilia and Cariri in Brazil. Well-defined magnetic field-aligned depletions were observed from each of these sites enabling detailed measurements of their morphology and dynamics. These data have also been used to investigate day-to-day and longitudinal variations in the evolution and distribution of the plasma bubbles, and their nocturnal zonal drift velocities. In particular, comparative optical measurements at different longitudinal sectors illustrated interesting findings. During the post midnight period, the data from Christmas Island consistently showed nearly constant eastward bubble velocity at a much higher value (~80 m/s) than expected, while data from Ascension Island exhibited a most unusual shear motion of the bubble structure, up to 55 m/s, on one occasion with westward drift at low latitude and eastward at higher latitudes, evident within the field of view of the camera. In addition, long-term radar observations during 1996-2006 from Jicamarca, Peru have been used to study the climatology of post-sunset ESF irregularities. Results showed that the spread F onset times did not change much with solar flux and that their onset heights increased linearly from solar minimum to solar maximum. On average, radar plume onset occurred earlier with increasing solar flux, and plume onset and peak altitudes increased with solar activity. The F-region upward drift velocities that precede spread F onset increased from solar minimum to solar maximum, and were approximately proportional to the maximum prereversal drift peak velocities.
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Mohd, Ali Aiffah. "GNSS in aviation : ionospheric threats at low latitudes." Thesis, University of Bath, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.761026.

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Radio signals propagating through the ionised upper atmosphere (the ionosphere) in low latitude regions of the world can experience amplitude scintillation. This could threaten safety-critical applications of satellite navigation such as aviation. The research presented here studied the effects of amplitude scintillation on a Septentrio PolaRxS geodetic receiver and a Garmin 480 aviation receiver by means of a Spirent GNSS constellation simulator. Different types of fade profiles showed that an abrupt drop in signal strength caused a loss of lock on the signal more often than a profile with a slow, gradual fade. A performance comparison of the two receivers demonstrated that the aviation receiver was more vulnerable than the geodetic receiver. An unexpected loss of lock at a specific fade duration and depth was seen with the Garmin receiver and was not explained. A single fade with a long fade duration was more likely to cause a loss of signal lock compared to rapid multiple fades. Scintillation on signals from low elevation satellites can significantly degrade the precision and integrity of the navigation solution in an aviation receiver; especially if the satellites are within the best geometrical set. RAIM was observed to be no longer available during the critical landing approach phase of the scenario, in the case when all satellites in view were affected by the scintillation-induced signal perturbations. A technique was also developed to simulate L5 scintillation based on real scintillation events of L1, in the absence of real captured data for L5. This was done to enable future investigations on aviation receiver performance when both L1 and L5 frequencies experience scintillation. Analysis indicated that L5 signal can be more vulnerable to the scintillation compared to the L1 signal, which may have important implications for aviation safety.
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Norton, Andrew David. "Analysis of Ionospheric Data Sets to Identify Periodic Signatures Matching Atmospheric Planetary Waves." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/101791.

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Atmospheric planetary waves play a role in introducing variability to the low-latitude ionosphere. To better understand this coupling, this study investigates times when oscillations seen in both atmospheric planetary waves and ionospheric data-sets have similar periodicity. The planetary wave data-set used are temperature observations made by Sounding of the Atmosphere using Broadband Emission Radiometry (SABER). These highlight periods during which 2-Day westward propagating wave-number 3 waves are evident in the mesosphere and lower thermosphere. The ionospheric data-set is Total Electron Content (TEC), which is used to identify periods during which the ionosphere appears to respond to the planetary waves. Data from KP and F10.7 indices are used to determine events that may be of external origin. A 17-year time-span from 2002 to 2018 is used for this analysis so that both times of solar minimum and maximum can be studied. To extract the periods of this collection of data a Morlet Wavelet analysis is used, along with thresholding to indicate events when similar periods are seen in each data-set. Trends are then determined, which can lead to verification of previous assumptions and new discoveries.
Master of Science
The thermosphere and ionosphere are impacted by many sources. The sun and the magnetosphere externally impact this system. Planetary waves, which originate in the lower atmosphere, internally impact this system. This interaction leads to periodic signatures in the ionosphere that reflect periodic signatures seen in the lower atmosphere, the sun and the magnetosphere. This study identifies these times of similar oscillations in the neutral atmosphere, the ionosphere, and the sun, in order to characterize these interactions. Events are cataloged through wavelet analysis and thresholding techniques. Using a time-span of 17 years, trends are identified using histograms and percentages. From these trends, the characteristics of this coupling can be concluded. This study is meant to confirm the theory and provide new insights that will hopefully lead to further investigation through modeling. The goal of this study is to gain a better understanding of the role that planetary waves have on the interaction of the atmosphere and the ionosphere.
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Khadka, Sovit M. "Multi-diagnostic Investigations of the Equatorial and Low-latitude Ionospheric Electrodynamics and Their Impacts on Space-based Technologies." Thesis, Boston College, 2018. http://hdl.handle.net/2345/bc-ir:108001.

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Thesis advisor: Prof. Michael J. Naughton
Thesis advisor: Dr. Cesar E. Valladares
The equatorial and low-latitude ionosphere of the Earth exhibits unique features on its structuring, coupling, and electrodynamics that offer the possibility to forecast the dynamics and fluctuations of ionospheric plasma densities at later times. The scientific understanding and forecasting of ionospheric plasma are necessary for several practical applications, such as for mitigating the adverse effects of space weather on communication, navigation, power grids, space mission, and for various scientific experiments and applications. The daytime equatorial electrojet (EEJ), equatorial ionization anomaly (EIA), as well as nighttime equatorial plasma bubble (EPB) and plasma blobs are the most prominent low-latitude ionospheric phenomena. This dissertation focuses on the multi-diagnostic study of the mechanism, properties, abnormalities, and interrelationships of these phenomena to provide significant contributions to space weather communities from the ground- and space-based measurements. A strong longitudinal, seasonal, day-to-day variability and dependency between EEJ, ExB vertical plasma drift, and total electron content (TEC) in the EIA distribution are seen in the equatorial and low-latitude region. In general, the EEJ strength is stronger in the west coast of South America than in its east coast. The variability of the EEJ in the dayside ionosphere significantly affects the ionospheric electron density variation, dynamics of the peak height of F2-layer, and TEC distributions as the EEJ influences the vertical transport mechanism of the ionospheric plasma. The eastward electric field (EEF) and the neutral wind play a decisive role in controlling the actual configuration of the EIA. The trans-equatorial neutral wind profile calculated using data from the Second-generation, Optimized, Fabry-Perot Doppler Imager (SOFDI) located near the geomagnetic equator and a physics-based numerical model, LLIONS (Low-Latitude IONospheric Sector) give new perspectives on the effects of daytime meridional neutral winds on the consequent evolution of the asymmetry of the equatorial TEC anomalies during the afternoon onwards. The spatial configurations including the strength, shape, amplitude and latitudinal extension of the EIA crests are affected by the EEF associated with the EEJ under undisturbed conditions, whereas the meridional neutral winds play a significant role in the development of their asymmetric structure in the low-latitude ionosphere. Additionally, the SWARM satellite constellation and the ground-based LISN (Low-Latitude Ionospheric Sensor Network) data allow us to resolve the space-time ambiguity of past single-satellite studies and detect the drastic changes that EPBs and plasma blobs undergo on a short time scale. The coordinated quantitative analysis of a plasma density observation shows evidence of the association of plasma blobs with EPBs via an appropriate geomagnetic flux tube. Plasma blobs were initially associated with the EPBs and remained at the equatorial latitude right above the EPBs height, but later were pushed away from geomagnetic equator towards EIA latitudes by the EPB/ depleted flux tubes that grew in volume. Further, there exists a strong correlation between the noontime equatorial electrojet and the GPS-derived TEC distributions during the afternoon time period, caused by vertical E × B drift via the fountain effect. Nevertheless, only a minor correlation likely exists between the peak EEJ and the net postsunset ionospheric scintillation index (S4) greater than 0.2. This study not only searches for a mutual relationship between the midday, afternoon and nighttime ionospheric phenomena but also aims at providing a possible route to improve our space weather forecasting capability by predicting nighttime ionospheric irregularities based on midday measurements at the equatorial and low latitudes
Thesis (PhD) — Boston College, 2018
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Physics
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Orford, Nicola Diane. "Behaviour of quiet time ionospheric disturbances at African equatorial and midlatitude regions." Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/62672.

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Extreme ionospheric and geomagnetic disturbances affect technology adversely. Prestorm enhancements, considered a potential predictor of geomagnetic storms, occur during quiet conditions prior to geomagnetic disturbances. The ionosphere experiences general disturbances during quiet geomagnetic conditions and these Q- disturbances remain unexplored over Africa. This study used TEC data to characterize the morphology of Q-disturbances over Africa, exploring variations with solar cycle, season, time of occurrence and latitude. Observations from 10 African GPS stations in the equatorial and midlatitude regions show that Q-disturbances in the equatorial region are predominantly driven by E x B variations, while multiple mechanisms affect the midlatitude region. Q- disturbances occur more frequently during nighttime than during daytime and no seasonal trend is observed. Midlatitude Q-disturbance mechanisms are explored in depth, considering substorm activity, the plasmaspheric contribution to GPS TEC and plasma transfer between conjugate points. Substorm activity is not a dominant mechanism, although Q-disturbances occurring under elevated substorm conditions tend to have longer duration and larger amplitude than general Q-disturbances. Many observed Q-disturbances become non-significant once the plasmaspheric contribution to the TEC measurements is removed, indicating that these disturbances occur within the plasmasphere, and not the ionosphere. Transfer of plasma between conjugate points does not seem to be a mechanism driving Q-disturbances, as the corresponding nighttime behaviour expected between depletions in the summer hemisphere and enhancements in the winter hemisphere is not observed. Pre-storm enhancements occur infrequently, rendering them a poor predictor of geomagnetic disturbances. Pre-storm enhancement morphology does not differ significantly from general quiet time enhancement morphology, suggesting pre-storms are not a special case of Q-disturbances.
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李若愚 and Yeuk-Yue Tony Li. "The equatorial ionospheric anomaly in East Asia from solar minimun to solar maximum." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B31211677.

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Li, Yeuk-Yue Tony. "The equatorial ionospheric anomaly in East Asia from solar minimum to solar maximum /." [Hong Kong : University of Hong Kong], 1993. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13597577.

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Matamba, Tshimangadzo Merline. "Long-term analysis of ionospheric response during geomagnetic storms in mid, low and equatorial latitudes." Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/63991.

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Understanding changes in the ionosphere is important for High Frequency (HF) communications and navigation systems. Ionospheric storms are the disturbances in the Earth’s upper atmosphere due to solar activities such as Coronal Mass Ejections (CMEs), Corotating interaction Regions (CIRs) and solar flares. This thesis reports for the first time on an investigation of ionospheric response to great geomagnetic storms (Disturbance storm time, Dst ≤ −350 nT) that occurred during solar cycle 23. The storm periods analysed were 29 March - 02 April 2001, 27 - 31 October 2003, 18 - 23 November 2003 and 06 - 11 November 2004. Global Navigation Satellite System (GNSS), Total Electron Content (TEC) and ionosonde critical frequency of F2 layer (foF2) data over northern hemisphere (European sector) and southern hemisphere (African sector) mid-latitudes were used to study the ionospheric responses within 15E° - 40°E longitude and ±31°- ±46° geomagnetic latitude. Mid-latitude regions within the same longitude sector in both hemispheres were selected in order to assess the contribution of the low latitude changes especially the expansion of Equatorial Ionization Anomaly (EIA) also known as the dayside ionospheric super-fountain effect during these storms. In all storm periods, both negative and positive ionospheric responses were observed in both hemispheres. Negative ionospheric responses were mainly due to changes in neutral composition, while the expansion of the EIA led to pronounced positive ionospheric storm effect at mid-latitudes for some storm periods. In other cases (e.g 29 October 2003), Prompt Penetration Electric Fields (PPEF), EIA expansion and large scale Traveling Ionospheric Disturbances (TIDs) were found to be present during the positive storm effect at mid-latitudes in both hemispheres. An increase in TEC on the 28 October 2003 was because of the large solar flare with previously determined intensity of X45± 5. A further report on statistical analysis of ionospheric storm effects due to Corotating Interaction Region (CIR)- and Coronal Mass Ejection (CME)-driven storms was performed. The storm periods analyzed occurred during the period 2001 - 2015 which covers part of solar cycles 23 and 24. Dst≤ -30 nT and Kp≥ 3 indices were used to identify the storm periods considered. Ionospheric TEC derived from IGS stations that lie within 30°E - 40°E geographic longitude in mid, low and equatorial latitude over the African sector were used. The statistical analysis of ionospheric storm effects were compared over mid, low and equatorial latitudes in the African sector for the first time. Positive ionospheric storm effects were more prevalent during CME-driven and CIR-driven over all stations considered in this study. Negative ionospheric storm effects occurred only during CME-driven storms over mid-latitude stations and were more prevalent in summer. The other interesting finding is that for the stations considered over mid-, low, and equatorial latitudes, negative-positive ionospheric responses were only observed over low and equatorial latitudes. A significant number of cases where the electron density changes remained within the background variability during storm conditions were observed over the low latitude stations compared to other latitude regions.
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Xu, Dongyang. "BEIDOU AND GPS DUAL CONSTELLATION VECTOR TRACKING DURING IONOSPHERE SCINTILLATION AT EQUATORIAL REGION." Miami University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1407512226.

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Galmiche, Aurélien. "Modélisation de la scintillation ionosphérique en zone équatoriale : application à l'inversion des signaux GNSS pour la caractérisation de la turbulence." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30053.

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L'ionosphère est un milieu ionisé dont les variations spatiales et temporelles de densité électronique perturbent la propagation des ondes électromagnétiques. En particulier, la nature turbulente du plasma ionosphérique conduit à des fluctuations rapides de l'amplitude et de la phase des signaux radioélectriques : c'est le phénomène de scintillation ionosphérique dont les effets sont particulièrement sensibles aux latitudes équatoriales sur les systèmes ayant un besoin accru de précision, de disponibilité et d'intégrité de la mesure, tel que les systèmes de localisation GNSS. L'objectif de cette thèse est justement d'exploiter de façon opportune les effets de la scintillation ionosphérique sur le signal pour proposer un sondage des caractéristiques de l'ionosphère turbulente par inversion des mesures GNSS. Dans un premier temps, les spécificités de la dynamique du plasma ionosphérique équatorial responsable des effets de scintillation sont rappelées. Ensuite, à partir d'une description spectrale des fluctuations turbulentes de densité électronique, une modélisation analytique puis numérique de la propagation transionosphérique sont proposées. Celles-ci sont complétées par la prise en compte du récepteur GNSS, finalisant la modélisation du problème direct. À ce stade, un algorithme d'inversion original des données GNSS est proposé. Son application intensive à la base de données SAGAIE collectée en Afrique équatoriale démontre alors la capacité de l'approche inverse à restituer divers paramètres descriptifs de la turbulence ionosphérique
The ionosphere is an ionized medium, into which the spatio-temporal electronic density variations disrupt the electromagnetic waves propagation. The turbulent ionospheric plasma is in particular linked to rapid amplitude and phase fluctuations of the radio electric signals: this is the ionospheric scintillation phenomenon. Especially around the equatorial latitudes, systems needing great accuracy, availability and measurement integrity are particularly sensitive to its effects. This is the case of the positioning systems using the GNSS technology. The aim of this thesis is to exploit insightly the ionospheric scintillation effects on the signal in order to propose a turbulent ionosphere's characteristics sounding through GNSS measurements inversion. At first, the specificities of the ionosphere's plasma dynamics accounting for the scintillation effects are reminded. Then, from a spectral description of the electronic density's turbulent fluctuations, an analytic and a numeric model of the transionospheric propagation are introduced. They are completed by considering the GNSS receiver. This step finalizes the direct problem's modelization. A new GNSS data inversion algorithm is then come up with. Its intensive application to the SAGAIE database (collected in equatorial Africa) shows the invers approach's capacity to return various parameters describing the ionospheric turbulences
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Books on the topic "Equatorial ionospheric"

1

McKinstry, John W. A comparison of trans-equatorial ionosphere propagation predictions from AMBCOM with measured data. Monterey, Calif: Naval Postgraduate School, 1993.

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International Reference Ionosphere Workshop on the Description of the Low Latitude and Equatorial Ionosphere in the IRI (2001 São José dos Campos, Brazil). Description of the low latitude and equatorial ionosphere in the international reference ionosphere: Refereed papers from the 2001 International Reference Ionosphere (IRI) Workshop on the Description of the low latitude and equatorial ionosphere in the IRI which was held at the INPE headquarters, São Josédos Campos, Brazil, 25-29 June, 2001. Oxford: Published for The Committee on Space Research [by] Pergamon, 2003.

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United States. National Aeronautics and Space Administration., ed. A study of the generation mechanisms of high-latitude and equatorial F-region irregularities using DE-2 data: Semi-annual report, August 1, 1984 - January 31, 1985. [Washington, D.C.?: National Aeronautics and Space Administration?, 1985.

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Symposium, COSPAR International Scientific. Low and equatorial latitudes in the International Reference Ionosphere (IRI): Proceedings of the COSPAR International Scientific Symposium held in New Delhi, India, 9-13 January 1995 / edited by K. Rawer ... [et al.]. Oxford, Eng: Published for the Committee on Space Research [by] Pergamon, 1996.

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Mukherjee, Shweta, P. K. Purohit, and A. K. Gwal. Ionospheric study of Equatorial Anomaly Station. LAP Lambert Academic Publishing, 2012.

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Mitra, A. P., Kanti K. Mahajan, D. Bilitza, K. K. Mahajan, A. P. Mitra, and K. Rawer. Low and Equatorial Latitudes in the International Reference Ionosphere (IRI). Elsevier Science Pub Co, 1996.

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Book chapters on the topic "Equatorial ionospheric"

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Moldwin, Mark B., and Justin S. Tsu. "Stormtime Equatorial Electrojet Ground-Induced Currents." In Ionospheric Space Weather, 33–40. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781118929216.ch3.

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Doumbia, Vafi, and Oswald Didier Franck Grodji. "On the Longitudinal Dependence of the Equatorial Electrojet." In Ionospheric Space Weather, 115–25. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781118929216.ch10.

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Huba, Joseph D. "Effect of Magnetic Declination on Equatorial SpreadFBubble Development." In Ionospheric Space Weather, 255–61. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781118929216.ch20.

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Somoye, Emmanuel O., Andrew O. Akala, Aghogho Ogwala, Eugene O. Onori, Rasaq A. Adeniji-Adele, and Enerst E. Iheonu. "Longitudinal Dependence of Day-to-Day Variability of Critical Frequency of Equatorial Type SporadicE(foEsq)." In Ionospheric Space Weather, 155–62. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781118929216.ch13.

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Fejer, B. G. "Equatorial Ionospheric Electric Fields Associated with Magnetospheric Disturbances." In Solar Wind — Magnetosphere Coupling, 519–45. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4722-1_37.

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Zanetti, L. J., T. A. Potemra, T. Iijima, and W. Baumjohann. "Equatorial, Birkeland, and Ionospheric Currents of the Magnetospheric Storm Circuit." In Magnetospheric Substorms, 111–22. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm064p0111.

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Chau, Jorge L., Larisa P. Goncharenko, Bela G. Fejer, and Han-Li Liu. "Equatorial and Low Latitude Ionospheric Effects During Sudden Stratospheric Warming Events." In Dynamic Coupling Between Earth’s Atmospheric and Plasma Environments, 385–417. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-5677-3_13.

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Palit, Sourav. "Numerical Simulation of Equatorial Ionospheric Response to Extra-Terrestrial High Energy Phenomena Using Ion Chemistry Models." In Astrophysics and Space Science Proceedings, 571–84. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-94607-8_44.

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Faturahman, Agri, Varuliantor Dear, Jiyo, Afrizal Bahar, Asnawi Husin, and Rezy Pradipta. "Ionospheric Observation Using Equatorial Atmosphere Radar (EAR) Kototabang for the 26 December 2019 Annular Solar Eclipse Research." In Springer Proceedings in Physics, 287–94. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-0308-3_23.

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Lin, Tao, and Gérard Lachapelle. "Demonstration of Signal Tracking and Scintillation Monitoring Under Equatorial Ionospheric Scintillation with a Multi-Frequency GNSS Software Receiver." In Lecture Notes in Electrical Engineering, 775–86. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-54737-9_67.

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Conference papers on the topic "Equatorial ionospheric"

1

Mokhtar, M. H., N. A. Rahim, M. Y. Ismail, and S. M. Buhari. "Ionospheric Perturbation: A Review of Equatorial Plasma Bubble in the Ionosphere." In 2019 6th International Conference on Space Science and Communication (IconSpace). IEEE, 2019. http://dx.doi.org/10.1109/iconspace.2019.8905970.

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Norsuzila Ya'acob, Mahamod Ismail, and Mardina Abdullah. "Investigation of the GPS signals ionospheric correction: Ionospheric TEC prediction over equatorial." In 2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications. IEEE, 2007. http://dx.doi.org/10.1109/ictmicc.2007.4448646.

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Gladek, Yuri C., Jonas Sousasantos, Lucas Salles, Vicente C. Lima Filho, Bruno Vani, and Alison de O. Moraes. "GPS Amplitude Fading Due to Ionospheric Scintillation Near the Equatorial Ionospheric Anomaly." In AIAA Scitech 2019 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2019. http://dx.doi.org/10.2514/6.2019-0057.

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Morton, Yu, Harrison Bourne, Mark Carroll, Yu Jiao, Nazelie Kassabian, Steve Taylor, Jun Wang, Dongyang Xu, and Hang Yin. "Multi-constellation GNSS observations of equatorial ionospheric scintillation." In 2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS). IEEE, 2014. http://dx.doi.org/10.1109/ursigass.2014.6929773.

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Xu, Dongyang, and Yu (Jade) Morton. "BeiDou Signal Parameters Characterization During Strong Equatorial Ionospheric Scintillation." In 29th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2016). Institute of Navigation, 2016. http://dx.doi.org/10.33012/2016.14786.

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Iyer, K. N., M. A. Abdu, J. R. de Souza, M. N. Jivani, and B. M. Pathan. "Ionospheric Scintillations At Equatorial And Low Latitudes In India." In 7th International Congress of the Brazilian Geophysical Society. European Association of Geoscientists & Engineers, 2001. http://dx.doi.org/10.3997/2214-4609-pdb.217.419.

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Ya'acob, Norsuzila, Azita Laily Yusof, Azlina Idris, Darmawaty Mohd Ali, Mohd Tarmizi Ali, and Noor Hijjah Mohd Yusof. "Observation of equatorial ionospheric plasma bubbles at peninsular Malaysia." In 2012 IEEE Symposium on Computer Applications and Industrial Electronics (ISCAIE). IEEE, 2012. http://dx.doi.org/10.1109/iscaie.2012.6482107.

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MacDougall, John, M. A. Abdu, I. Batista, R. Buriti, P. T. Jayachandran, and G. Borba. "Equatorial travelling ionospheric disturbances (TIDs) compared with midlatitude TIDs." In 2011 XXXth URSI General Assembly and Scientific Symposium. IEEE, 2011. http://dx.doi.org/10.1109/ursigass.2011.6050927.

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Ji, Yifei, Yongsheng Zhang, Qilei Zhang, and Dong Zhen. "Elongation Orientation of Equatorial Ionospheric Irregularities in Spaceborne SAR Images." In 2019 6th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR). IEEE, 2019. http://dx.doi.org/10.1109/apsar46974.2019.9048370.

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Nagarajoo, K. "Ionospheric modelling in 3D over the equatorial region using IRI." In 2012 NATIONAL PHYSICS CONFERENCE: (PERFIK 2012). AIP, 2013. http://dx.doi.org/10.1063/1.4803627.

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Reports on the topic "Equatorial ionospheric"

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Comberiate, Joseph M. Space-Based Three-Dimensional Imaging of Equatorial Plasma Bubbles: Advancing the Understanding of Ionospheric Density Depletions and Scintillation. Fort Belvoir, VA: Defense Technical Information Center, March 2012. http://dx.doi.org/10.21236/ada567064.

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Pakula, W. A., J. A. Klobuchar, D. N. Anderson, and P. H. Doherty. Ionospheric Errors at L-Band for Satellite and Re-Entry Object Tracking in the New Equatorial Anomaly Region. Fort Belvoir, VA: Defense Technical Information Center, May 1990. http://dx.doi.org/10.21236/adp006303.

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Liu, Chao-Han. Study of Equatorial Ionospheric Irregularities with ROCSAT- 1/IPEI Data for Assessment of Impacts on Communication/Navigation System (V). Fort Belvoir, VA: Defense Technical Information Center, November 2009. http://dx.doi.org/10.21236/ada512634.

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Sales, Gary S. The Effect of Equatorial Ionospheric Irregularities on the Performance of a South-Looking OTH-B (Over-The-Horiozon-Backscatter) Radar. Fort Belvoir, VA: Defense Technical Information Center, October 1987. http://dx.doi.org/10.21236/ada195090.

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Jenan, R., T. L. Dammalage, and A. Kealy. The Influences of Solar Activities on TEC Variations of Equatorial Ionosphere over Sri Lanka. Balkan, Black sea and Caspian sea Regional Network for Space Weather Studies, March 2020. http://dx.doi.org/10.31401/sungeo.2019.02.05.

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Jenan, R., T. L. Dammalage, and A. Kealy. The Influences of Solar Activities on TEC Variations of Equatorial Ionosphere over Sri Lanka. Balkan, Black sea and Caspian sea Regional Network for Space Weather Studies, March 2020. http://dx.doi.org/10.31401/sungeo.2020.02.05.

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McDonald, Sarah, and Joseph Huba. An Investigation of the Seasonal Variation of Equatorial Electrodynamics and Scintillation Using a Coupled Atmosphere-Ionosphere Model. Fort Belvoir, VA: Defense Technical Information Center, January 2009. http://dx.doi.org/10.21236/ada531093.

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