GUVI Biblio


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Found 2061 entries in the Bibliography.

Showing entries from 101 through 150


Spatial structures in solar wind superthermal electrons and polar rain aurora

We report a special polar rain aurora case around 11:24 UT on October 27, 2003, where intense polar rain electrons produced observable polar rain auroral emission with the shape of a roughly dawn-dusk aligned bar. Associated solar wind speed and density observations during the event were around 450 km/s and 2.5 cm−3 respectively. The interplanetary magnetic field (IMF) components Bx, By, and Bz were \textasciitilde5, −3, and 5 nT respectively. The negative By condition likely caused the dawnside shift and slight tilt ...

Herschbach, Dennis; Zhang, Yongliang;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: jul

YEAR: 2021     DOI: 10.1016/j.jastp.2021.105633

Magnetosphere interaction; Polar rain aurora; Polar rain electrons; solar wind; Solar wind superthermal electrons

Quantifying the Impact of Dynamic Storm-Time Exospheric Density on Plasmaspheric Refilling

As soon as the outer plasmasphere gets eroded during geomagnetic storms, the greatly depleted plasmasphere is replenished by cold, dense plasma from the ionosphere. A strong correlation has been revealed between plasmaspheric refilling rates and ambient densities in the topside ionosphere and exosphere, particularly that of atomic hydrogen (H). Although measurements of H airglow emission at plasmaspheric altitudes exhibit storm-time response, temporally static distributions have typically been assumed in the H density in pla ...

Waldrop, Lara; Cucho-Padin, Gonzalo; site, this; Maruyama, Naomi; site, this;

Published by: Earth and Space Science Open Archive ESSOAr      Published on: jan

YEAR: 2021     DOI: 10.1002/essoar.10505771.1

Atmospheric Sciences; Atmospheric Sciences / Magnetospheric Particles

Understanding the role of exospheric density in the ring current recovery rate

Atomic Hydrogen (H) is the most abundant constituent of the terrestrial exosphere. Its charge exchange interaction with ring current ions (H+ and O+) serves to dissipate magnetospheric energy during geomagnetic storms, resulting in the generation of energetic neutral atoms (ENAs). Determination of ring current ion distributions through modeling depends critically on the specification of the exospheric H density distribution. Furthermore, theoretical studies have demonstrated that ring current recovery rate after the storm on ...

Cucho-Padin, Gonzalo; site, this; Ferradas, Cristian; Waldrop, Lara; Fok, Mei-Ching; site, this;

Published by: Earth and Space Science Open Archive ESSOAr      Published on: jan

YEAR: 2021     DOI: 10.1002/essoar.10505770.1

Atmospheric Sciences; Atmospheric Sciences / Magnetospheric Particles

A new method to subtract dayglow for auroral observation of SSUSI in LBH ranges based on the improved AURIC

A new method to remove the dayglow components for auroral observations from the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) aboard the Defense Meteorological Satellite Program (DMSP) F16 in Lyman-Birge-Hopfield (LBH) ranges based on the improved Atmospheric Ultraviolet Radiance Integrated Code (AURIC) algorithm is proposed in this study. This method is developed by determining the coefficients between the dayglow intensities calculated by the improved AURIC algorithm and the dayglow components from SSUSI in the ...

Wang, JiaKe; Ding, GuangXing; Yu, Miao; Wang, HaiFeng;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: jan

YEAR: 2021     DOI: 10.1016/j.jastp.2020.105517

AURIC; AURORA; dayglow; FUV observation

The ionospheric response to high-intensity long duration continuous AE activity (HILDCAA) event (13–15 April 2005) over mid-latitude African region

The ionospheric responses to High-Intensity Long Duration Continuous Auroral Electrojet Activity (HILDCAA) event which happened following the CIR-driven storm were studied over the southern hemisphere mid-latitude in the African sector. The 13–15 April 2005 event was analysed to understand some of the mechanisms responsible for the ionospheric changes during HILDCAA event. The ionosonde critical frequency of F2 layer (foF2) and Global Navigation Satellite System (GNSS) Total Electron Content (TEC) were used to analyse the ...

Matamba, Tshimangadzo; Habarulema, John;

Published by: Advances in Space Research      Published on: jan

YEAR: 2021     DOI: 10.1016/j.asr.2020.10.034

CIR; HILDCAA; Ionospheric storm; PPEF; TEC; TIDs

Longitudinal variations of geomagnetic and ionospheric parameters in the Northern Hemisphere during magnetic storms according to multi-instrument observations

We present a joint analysis of longitude-temporal variations of ionospheric and geomagnetic parameters at middle and high latitudes in the Northern Hemisphere during the two severe magnetic storms in March and June 2015 by using data from the chains of magnetometers, ionosondes and GPS/GLONASS receivers. We identify the fixed longitudinal zones where the variability of the magnetic field is consistently high or low under quiet and disturbed geomagnetic conditions. The revealed longitudinal structure of the geomagnetic field ...

Chernigovskaya, M.; Shpynev, B.; Yasyukevich, A.; Khabituev, D.; Ratovsky, K.; Belinskaya, Yu.; Stepanov, A.; Bychkov, V.; Grigorieva, S.; Panchenko, V.; Kouba, D.; Mielich, J.;

Published by: Advances in Space Research      Published on: jan

YEAR: 2021     DOI: 10.1016/j.asr.2020.10.028

Chain of GPS/GLONASS receivers; Geomagnetic field variations; geomagnetic storm; Ionosonde chain; ionospheric disturbances

Auroral ionospheric E region parameters obtained from satellite- based far-ultraviolet and ground-based ionosonde observations – effects of proton precipitation

\textlessp\textgreater\textlessstrong class="journal-contentHeaderColor"\textgreaterAbstract.\textless/strong\textgreater Coincident auroral far-ultraviolet (FUV) and ground-based ionosonde observations are compared for the purpose of determining whether auroral FUV remote sensing algorithms that assume pure electron precipitation are biased in the presence of proton precipitation. Auroral particle transport and optical emission models, such as the Boltzmann 3-Constituent (B3C) model, predict that maximum E region electron d ...

Knight, Harold;

Published by: Annales Geophysicae      Published on: jan

YEAR: 2021     DOI: 10.5194/angeo-39-105-2021

A ROTI-Aided Equatorial Plasma Bubbles Detection Method

In this study, we present a Rate of Total Electron Content Index (ROTI)-aided equatorial plasma bubbles (EPBs) detection method based on a Global Navigation Satellite System (GNSS) ionospheric Total Electron Content (TEC). This technique seeks the EPBs occurrence time according to the ROTI values and then extracts the detrended ionospheric TEC series, which include EPBs signals using a low-order, partial polynomial fitting strategy. The EPBs over the Hong Kong area during the year of 2014 were detected using this technique. ...

Tang, Long; Louis, Osei-Poku; Chen, Wu; Chen, Mingli;

Published by: Remote Sensing      Published on: jan

YEAR: 2021     DOI: 10.3390/rs13214356

Ionosphere; detection method; equatorial plasma bubbles; GNSS; ROTI

Ionospheric response to solar and magnetospheric protons during January 15–22, 2005: EAGLE whole atmosphere model results

We present an analysis of the ionosphere and thermosphere response to Solar Proton Events (SPE) and magnetospheric proton precipitation in January 2005, which was carried out using the model of the entire atmosphere EAGLE. The ionization rates for the considered period were acquired from the AIMOS (Atmospheric Ionization Module Osnabrück) dataset. For numerical experiments, we applied only the proton-induced ionization rates of that period, while all the other model input parameters, including the electron precipitations, c ...

Bessarab, F.; Sukhodolov, T.; Klimenko, M.; Klimenko, V.; Korenkov, Yu.; Funke, B.; Zakharenkova, I.; Wissing, J.; Rozanov, E.;

Published by: Advances in Space Research      Published on: jan

YEAR: 2021     DOI: 10.1016/j.asr.2020.10.026

Ionosphere; Proton precipitations; Solar proton events; thermosphere; Whole atmosphere model

Ionospheric response to the 17 March and 22 June 2015 geomagnetic storms over Wuhan region using GNSS-based tomographic technique

By using the data of GNSS (Global Navigation Satellite System) observation from Crustal Movement Observation Network of China (CMONOC), ionospheric electron density (IED) distributions reconstructed by using computerized ionospheric tomography (CIT) technique are used to investigate the ionospheric storm effects over Wuhan region during 17 March and 22 June 2015 geomagnetic storm periods. F-region critical frequency (foF2) at Wuhan ionosonde station shows an obvious decrease during recovery phase of the St. Patrick’s Day g ...

Feng, Jian; Zhou, Yufeng; Zhou, Yan; Gao, Shuaihe; Zhou, Chen; Tang, Qiong; Liu, Yi;

Published by: Advances in Space Research      Published on: jan

YEAR: 2021     DOI: 10.1016/j.asr.2020.10.008

Ionospheric electron density distributions; ionospheric storm effects; Multiplication algebraic reconstruction technique

Simplified Approach to Detect Satellite Maneuvers Using TLE Data and Simplified Perturbation Model Utilizing Orbital Element Variation

In this study, an algorithm to identify the maneuvers of a satellite is developed by comparing the Keplerian elements acquired from the two-line elements (TLEs) and Keplerian elements propagated from simplified perturbation models. TLEs contain a specific set of orbital elements, whereas the simplified perturbation models are used to propagate the state vectors at a given time. By comparing the corresponding Keplerian elements derived from both methods, a satellite’s maneuver is identified. This article provides an outline ...

Mukundan, Arvind; Wang, Hsiang-Chen;

Published by: Applied Sciences      Published on: jan

YEAR: 2021     DOI: 10.3390/app112110181

Keplarian elements; simplified perturbation models; trial \& error and maneuver detection; two-line elements

B2 Thickness Parameter Response to Equinoctial Geomagnetic Storms

The thickness parameters that most empirical models use are generally defined by empirical relations related to ionogram characteristics. This is the case with the NeQuick model that uses an inflection point below the F2 layer peak to define a thickness parameter of the F2 bottomside of the electron density profile, which is named B2. This study is focused on the effects of geomagnetic storms on the thickness parameter B2. We selected three equinoctial storms, namely 17 March 2013, 2 October 2013 and 17 March 2015. To invest ...

Migoya-Orué, Yenca; Alazo-Cuartas, Katy; Kashcheyev, Anton; Amory-Mazaudier, Christine; Radicella, Sandro; Nava, Bruno; Fleury, Rolland; Ezquer, Rodolfo;

Published by: Sensors      Published on: jan

YEAR: 2021     DOI: 10.3390/s21217369

Geomagnetic storms; total electron content; ionospheric empirical models; NeQuick model; thickness parameter

Proton Aurora and Optical Emissions in the Subauroral Region

Optical structures located equatorward of the main auroral oval often exhibit different morphologies and dynamics than structures at higher latitudes. In some cases, questions arise regarding the formation mechanisms of these photon-emitting phenomena. New developments in space and ground-based instruments have enabled us to acquire a clearer view of the processes playing a role in the formation of subauroral structures. In addition, the discovery of new optical structures helps us improve our understanding of the latitudina ...

Gallardo-Lacourt, B.; Frey, H.; Martinis, C.;

Published by: Space Science Reviews      Published on: jan

YEAR: 2021     DOI: 10.1007/s11214-020-00776-6

Optical structures; Subauroral region

Responses of the African equatorial ionization anomaly (EIA) to some selected intense geomagnetic storms during the maximum phase of solar cycle 24

This study investigates the morphology of the GPS TEC responses in the African Equatorial Ionization Anomaly (EIA) region to intense geomagnetic storms during the ascending and maximum phases of solar cycle 24 (2012–2014). Specifically, eight intense geomagnetic storms with Dst ≤ −100 nT were considered in this investigation using TEC data obtained from 13 GNSS receivers in the East African region within 36–42°E geographic longitude; 29°N–10°S geographic latitude; ± 20°N magnetic latitude. The storm-time beh ...

Oyedokun, O.; Akala, A.; Oyeyemi, E.;

Published by: Advances in Space Research      Published on: feb

YEAR: 2021     DOI: 10.1016/j.asr.2020.11.020

African equatorial ionization anomaly; geomagnetic storm; GNSS; Ionosphere

Features of topside ionospheric background over China and its adjacent areas obtained by the ZH-1 satellite

\textlessp\textgreaterTopside ionospheric background distribution and its seasonal variations over China and its adjacent areas, e.g. 0°-54°N and 70°-140°E, are studied using the in situ electron density (Ne) measurements obtained by the LAP payload on board the ZH-1 (CSES) satellite. Results are as followings:(1) Regularities consistent with results from previous studies are shown on the latitudinal extension, longitudinal distribution, and seasonal variations of the EIA (Equatorial Ionization Anomaly) phenomenon in the ...

XiuYing, Wang; DeHe, Yang; ZiHan, Zhou; Jing, C.; Na, Zhou; XuHui, Shen;

Published by: Chinese Journal of Geophysics      Published on: feb

YEAR: 2021     DOI: 10.6038/cjg2021O0152

Latitudinal Dependence of the Ionospheric Slab Thickness for Estimation of Ionospheric Response to Geomagnetic Storms

The changes in the ionosphere during geomagnetic disturbances is one of the prominent Space Weather effects on the near-Earth environment. The character of these changes can differ significantly at different regions on the Earth. We studied ionospheric response to five geomagnetic storms of March 2012, using data of Total Electron Content (TEC) and F2-layer critical frequency (foF2) along the meridian of 70° W in the Northern Hemisphere. There are few ionosondes along this longitudinal sector: in Thule, Sondrestrom, Millsto ...

Sergeeva, Maria; Maltseva, Olga; Caraballo, Ramon; Gonzalez-Esparza, Juan; Corona-Romero, Pedro;

Published by: Atmosphere      Published on: feb

YEAR: 2021     DOI: 10.3390/atmos12020164

foF2; geomagnetic storm; Ionospheric disturbance; ionospheric equivalent slab thickness; statistical analysis; TEC

Spread-F occurrence during geomagnetic storms near the southern crest of the EIA in Argentina

This work presents, for the first time, the analysis of the occurrence of ionospheric irregularities during geomagnetic storms at Tucumán, Argentina, a low latitude station in the Southern American longitudinal sector (26.9°S, 294.6°E; magnetic latitude 15.5°S) near the southern crest of the equatorial ionization anomaly (EIA). Three geomagnetic storms occurred on May 27, 2017 (a month of low occurrence rates of spread-F), October 12, 2016 (a month of transition from low to high occurrence rates of spread-F) and November ...

González, Gilda;

Published by: Advances in Space Research      Published on: feb

YEAR: 2021     DOI: 10.1016/j.asr.2020.10.051

Geomagnetic storms; ionospheric irregularities; space weather; Spread-F

Improved model of ionosphere variability and study for long-term statistical characteristics

Ionospheric variability is influenced by many factors, such as solar radiation, neutral atmosphere composition, and geomagnetic disturbances. Mainly characterized by the total electron content (TEC) and electron density, the climatology of the ionosphere features temporal and spatial changes. Establishing a multivariant regression model helps substantially in better understanding the ionosphere characteristics and their long-term variability. In this paper, an improvement of the existing ionosphere multivariate linear fittin ...

Bin, Xueheng; Liu, Yang;

Published by: Chinese Journal of Aeronautics      Published on: feb

YEAR: 2021     DOI: 10.1016/j.cja.2020.03.018

total electron content; Analysis of anomalies; Long-term statistics; Regression model

Assessing the performance of a Northeast Asia Japan-centered 3-D ionosphere specification technique during the 2015 St. Patrick’s day geomagnetic storm

This paper demonstrates and assesses the capability of the advanced three-dimensional (3-D) ionosphere tomography technique, during severe conditions. The study area is northeast Asia and quasi-Japan-centred. Reconstructions are based on total electron content data from a dense ground-based global navigation satellite system receiver network and parameters from operational ionosondes. We used observations from ionosondes, Swarm satellites and radio occultation (RO) to assess the 3-D picture. Specifically, we focus on St. Pat ...

Nicholas, Ssessanga; Mamoru, Yamamoto; Susumu, Saito;

Published by: Earth, Planets and Space (Online)      Published on: dec

YEAR: 2021     DOI: 10.1186/s40623-021-01447-8

geomagnetic storm; Ground-GNSS-STEC tomography; Ionosonde data assimilation

Teleseismic measurements of upper mantle shear wave anisotropy in the Isthmus of Tehuantepec, Mexico

Shear wave splitting measurements in the Isthmus of Tehuantepec (IT), southern Mexico, inferred from teleseismic core phases are presented. Measurements were made along a south-to-north profile across the IT. The results show a predominantly trench-normal pattern of fast polarization orientations with averaged delay times up to 2.2 s. Fast orientations near the trench suggest a corner flow in the mantle wedge and an entrained flow in the subslab region. Away the trench, fast orientations are parallel to the Absolute Plate M ...

León Soto, Gerardo; Valenzuela, Raúl; Arceo, R; Huesca-Pérez, Eduardo; Rosas, Ricardo;

Published by: Geophysical Journal International      Published on: dec

YEAR: 2021     DOI: 10.1093/gji/ggab301

Comparison of ionospheric anomalies over African equatorial/low-latitude region with IRI-2016 model predictions during the maximum phase of solar cycle 24

The capability of IRI-2016 in reproducing the hemispheric asymmetry, the winter and semiannual anomalies has been assessed over the equatorial ionization anomaly (EIA) during quiet periods of years 2013–2014. The EIA reconstructed using Total Electron Content (TEC) derived from Global Navigation Satellite System was compared with that computed using IRI-2016 along longitude 25° − 40oE. These were analyzed along with hemispheric changes in the neutral wind derived from the horizontal wind model and the TIMED GUVI columna ...

Amaechi, Paul; Oyeyemi, Elijah; Akala, Andrew; Kaab, Mohamed; Younas, Waqar; Benkhaldoun, Zouhair; Khan, Majid; Mazaudier, Christine-Amory;

Published by: Advances in Space Research      Published on: aug

YEAR: 2021     DOI: 10.1016/j.asr.2021.03.040

Equatorial ionization anomaly; hemispheric asymmetry; IRI-2016; Semiannual anomaly; Winter anomaly

Impact of CME and HSSW driven geomagnetic storms on thermosphere and ionosphere as observed from mid-latitudes

The present paper reports magnetospheric-thermospheric-ionospheric interactions, observed during geomagnetically disturbed periods in 2015–2016 from mid-latitude stations located in the US-Pacific longitudes (\textasciitilde120°W geographic). These interactions have been analyzed for a series of Coronal Mass Ejection (CME) and High Speed Solar Wind (HSSW) driven geomagnetic storms during the moderate solar activity periods. The geomagnetically disturbed periods under consideration in this paper have an interesting feature ...

Sur, Dibyendu; Ray, Sarbani; Paul, Ashik;

Published by: Advances in Space Research      Published on: aug

YEAR: 2021     DOI: 10.1016/j.asr.2021.03.027

CME and HSSW storms; Joule heating; Meridional and zonal wind; O/N ratio; Plasma transport; VTEC

Effect of intense geomagnetic storms on low-latitude TEC during the ascending phase of the solar cycle 24

The results presented in this paper are obtained from low-latitude ionospheric total electron content (TEC) variation during the chosen geomagnetic storm events happening during the solar cycle 24. We include the four intense geomagnetic storms that occurred on 26 September 2011, 15 July 2012, 19 February 2014 and 20 December 2015, depending upon the availability of TEC data. For this, we have used the TEC data from low-latitude station Varanasi (geographic latitude 25°, 16′N, geographic longitude 82°, 59′E and geomagn ...

Singh, Abha; Rathore, Vishnu; Kumar, Sanjay; Rao, S.; Singh, Sudesh; Singh, A.;

Published by: Journal of Astrophysics and Astronomy      Published on: aug

YEAR: 2021     DOI: 10.1007/s12036-021-09774-8

geomagnetic storm; Global positioning system; low latitude; total electron contents

Solar flares and geomagnetic storms of September 2017: Their impacts on the TEC over 75°E longitude sector

This study investigates the ionospheric Total Electron Content (TEC) responses over 75°E longitude to the solar flares and geomagnetic storms of September 6–9, 2017. The results of this study provide the impacts of solely solar flares on the ionosphere and such impact when the effects of solar flares and geomagnetic storm are combined. On September 6, two X class solar flares, namely X2.2 at 0857 UT and X9.3 at 1153 UT, were recorded with quiet geomagnetic conditions. The EUV/X-ray intensity of X9.3 flare was significan ...

Chakraborty, Monti; Singh, A.; Rao, S.;

Published by: Advances in Space Research      Published on: aug

YEAR: 2021     DOI: 10.1016/j.asr.2021.04.012

TEC; geomagnetic storm; EUV; Solar flare; X-ray

The Dynamics of the Alfvénic Oval

The auroral oval is a well-established concept, introduced more than five decades ago. The Alfvénic oval, on the other hand, is a very recent concept, which has been revealed in both observational and numerical studies. This is the first review of the global Alfvénic oval, while also defining primary, secondary and tertiary layers of the Alfvénic oval. The focus lies on the large-scale dynamic properties of the global Alfvénic oval in relation to the AE index, substorm phases, storm phases and solar wind/IMF conditions. ...

Keiling, Andreas;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: aug

YEAR: 2021     DOI: 10.1016/j.jastp.2021.105616

AURORA; Alfven wave; Energy transport; geomagnetic activity; magnetosphere-ionosphere coupling; Wave-particle interaction

Ultraviolet Observations and a Theory of STEVE

A search for ultraviolet (UV) emissions in satellite data during known STEVE (Strong Thermal Emission Velocity Enhancement) events found that simultaneous subauroral UV arcs (SUA) were usually, but not always present in the Southern Hemisphere despite coverage of the conjugate STEVE location. From 2005 to 2020 a systematic search for SUA found over 100 cases with a mean Magnetic Local Time (MLT) of 316°, standard deviation 13° and hemispheric asymmetry. Frequently coincident continuum UV and visible emissions, upwelling pl ...

Bennett, Charles; site, this;

Published by: Earth and Space Science Open Archive ESSOAr      Published on: apr

YEAR: 2021     DOI: 10.1002/essoar.10504577.6

Atmospheric Sciences; Atmospheric Sciences / Airglow; Atmospheric Sciences / Aurora; Atmospheric Sciences / Ionosphere; Atmospheric Sciences / Magnetospheric Particles; Atmospheric Sciences / Precipitation Physics; Atmospheric Sciences / Solar Wind

A Statistical Analysis of Plasma Bubbles Observed by Swarm Constellation during Different Types of Geomagnetic Storms

Based on the observations of Ionospheric Bubble Index (IBI) data from the Swarm mission, the characteristics of plasma bubbles are investigated during different types of geomagnetic storms recorded from 2014 to 2020. The geometrical constellation of the Swarm mission enabled us to investigate the altitudinal profile of the IBIs during different activity levels in a statistical mean. Results show that the majority of IBIs associated with moderate storms are observed at low altitudes and the probability of observing IBIs at hi ...

Hussien, Fayrouz; Ghamry, Essam; Fathy, Adel;

Published by: Universe      Published on: apr

YEAR: 2021     DOI: 10.3390/universe7040090

geomagnetic storm; ionospheric irregularity; plasma bubble; Swarm mission

Lower Thermospheric Material Transport via Lagrangian Coherent Structures

We show that inter-model variation due to under-constraint by observations impacts the ability to predict material transport in the lower thermosphere. Lagrangian coherent structures (LCSs), indicating regions of maximal separation (or convergence) in a time-varying flow, are derived in the lower thermosphere from models for several space shuttle water vapor plume events. We find that inter-model differences in thermospheric transport manifest in LCSs in a way that is more stringent than mean wind analyses. LCSs defined usin ...

Datta-Barua, Seebany; Pedatella, Nicholas; Greer, Katelynn; Wang, Ningchao; Nutter, Leanne; Harvey, Lynn;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028834

Periodic Variations in Solar Wind and Responses of the Magnetosphere and Thermosphere in March 2017

TIMED/GUVI observed thermospheric column ∑O/N2 depletion in both hemispheres between March 1 and 21, 2017 which was caused by large periodic variations in interplanetary magnetic field (IMF) and a high solar wind speed, likely in a solar wind. The dominant periods seen in the solar wind and magnetosphere coupling function (CF) were around 1.9, 3.0, 4.7, 7.6, 14.0 and 22.0 h on March 1 and 2. The major AE variations were around 3.0, 4.7, 7.6, 10.7, 14.0 and 22.0 h. Auroral hemispheric power (HP) also showed periodic variati ...

Zhang, Yongliang; Paxton, Larry; Wang, Wenbin; Huang, Chaosong;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029387

AE index; geomagnetic storm; hemispheric power; periodic variation; solar wind and magnetosphere coupling; thermospheric composition

Hemispheric Asymmetries in the Mid-latitude Ionosphere During the September 7–8, 2017 Storm: Multi-instrument Observations

Hemispheric asymmetries of the Vertical Total Electron Content (VTEC) were observed during the first recovery phase of the geomagnetic storm on September 7–8, 2017. These asymmetries occurred at the mid latitudes at two different local times simultaneously: In the European-African sector (early morning), the storm time VTEC in the southern/northern hemisphere was higher/lower than the quiet time value, suggesting the southern/northern hemisphere entered the positive/negative phase (N−S+). In the East Asian-Australian sec ...

Wang, Zihan; Zou, Shasha; Liu, Lei; Ren, Jiaen; Aa, Ercha;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028829

Longitudinal Variation of Postsunset Plasma Depletions From the Global-Scale Observations of the Limb and Disk (GOLD) Mission

The Global-scale Observations of the Limb and Disk (GOLD) mission, launched in 2018, aims to investigate the low latitude ionosphere from a geostationary orbit at 47.5°W. It uses two identical spectrometers measuring the wavelength range from 134.0 to 163.0 nm. The configuration of the Earth s magnetic field shows that the largest offset between geographic and geomagnetic equators occurs in the longitude sectors sampled by GOLD. In an attempt to investigate the longitude dependence of the occurrence rate and time of onset o ...

Martinis, C.; Daniell, R.; Eastes, R.; Norrell, J.; Smith, J.; Klenzing, J.; Solomon, S.; Burns, A.;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028510

F region; longitude variability; plasma bubbles; Plasma depletions; upward drifts

Observational Evidence and Formation Mechanism of Low-Density Cells in the Upper Thermosphere on September 8, 2017

The low-density cell structure in the high-latitude thermosphere is referred to as the density depletion with respect to the adjacent area. Based on Gravity Recovery and Climate Experiment (GRACE) accelerometer data during the September 2017 geomagnetic storms, the thermospheric mass density at about 350 km are estimated and further investigated especially in the high-latitude regions. At least two kinds of low-density cells over the Southern Hemisphere (SH) are observed along the GRACE orbit. To understand the low-density c ...

Yuan, Liangliang; Jin, Shuanggen;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028915

An Unusually Large Electron Temperature Increase Over Arecibo Associated With an Intense Geomagnetic Storm

We present an investigation of the F-region electron temperature to an intense geomagnetic storm that occurred on 5 August 2011. The investigation is based on the incoherent scatter radar measurements at Arecibo Observatory, Puerto Rico (18.3°N, 66.7°W). The electron temperature exhibits a rapid and intensive enhancement after the commencement of the geomagnetic storm. The electron temperature increases by ∼800 K within an hour, which is seldomly reported at Arecibo. At the same time, a depletion of the electron density ...

Lv, Xiedong; Gong, Yun; Zhang, ShaoDong; Zhou, Qihou; Ma, Zheng;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029836

Arecibo; F-region electron temperature; geomagnetic storm; incoherent scatter radar

Development and Validation of Precipitation Enhanced Densities for the Empirical Canadian High Arctic Ionospheric Model

The Empirical Canadian High Artic Ionospheric Model (E-CHAIM) provides the four-dimensional ionosphere electron density at northern high latitudes (\textgreater50° geomagnetic latitude). Despite its emergence as the most reliable model for high-latitude ionosphere density, there remain significant deficiencies in E-CHAIM s representation of the lower ionosphere (below ∼200 km) due to a sparsity of reliable measurements at these altitudes, particularly during energetic particle precipitation events. To address this deficie ...

Watson, C.; Themens, D.; Jayachandran, P.;

Published by: Space Weather      Published on:

YEAR: 2021     DOI: 10.1029/2021SW002779

auroral region; Ionosphere; ionosphere density; magnetosphere-ionosphere-thermosphere coupling; particle precipitation; polar cap

Wide-field aurora imager onboard Fengyun satellite: Data products and validation

New observations of auroras based on the wide-field aurora imager (WAI) onboard Fengyun-3D (FY-3D) satellite are exhibited in this paper. Validity of the WAI data is analyzed by comparing auroral boundaries derived from WAI observations with results obtained from data collected by the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) aboard the Defense Meteorological Satellite Program (DMSP F18). Dynamic variations of the aurora with the solar wind, interplanetary magnetic field (IMF) parameters, and the SYM-H index a ...

Ding, GuangXing; Li, JiaWei; Zhang, Xiaoxin; He, Fei; He, LingPing; Song, KeFei; Sun, Liang; Dai, Shuang; Liu, ShiJie; Chen, Bo; Yu, Chao; Hu, Xiuqing; Gu, SongYan; Yang, Zhongdong; Zhang, Peng;

Published by: Earth and Planetary Physics      Published on:

YEAR: 2021     DOI: 10.26464/epp2021003

auroral dynamics; FY-3D; SSUSI; SW-M-I; WAI

Understanding the Impacts of Mesosphere and Lower Thermosphere on Thermospheric Dynamics and Composition

The Earth’s Ionosphere and Thermosphere (IT) is a highly dynamic system persistently driven by variable forcings both from above (Solar EUV and the magnetosphere) and the lower atmosphere. The forcing from below accounts for the majority of the variability at low- and mid-latitude IT region during geomagnetic quiet times. The IT region is particularly sensitive to the composition, winds, and temperature of the Mesosphere and Lower Thermosphere (MLT) state. The goal of this dissertation is to help understand how the MLT reg ...

Malhotra, Garima;

Published by:       Published on:

YEAR: 2021     DOI: 10.7302/2811

Near Real-Time Global Plasma Irregularity Monitoring by FORMOSAT-7/COSMIC-2

This study presents initial results of the ionospheric scintillation in the F layer using the S4 index derived from the radio occultation experiment (RO-S4) on FORMOSAT-7/COSMIC-2 (F7/C2). With the sufficiently dense RO-S4 observations at low latitudes, it is possible to construct hourly, global scintillation maps to monitor equatorial plasma bubbles (EPBs). The preliminary F7/C2 RO-S4 during August 2019 to April 2020 show clear scintillation distributions around American and the Atlantic Ocean longitudes. The RO-S4 near Jic ...

Chen, Shih-Ping; Lin, Charles; Rajesh, Panthalingal; Liu, Jann-Yenq; Eastes, Richard; Chou, Min-Yang; Choi, Jong-Min;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028339

equatorial plasma bubbles; FORMOSAT-7/COSMIC-2; global observation of limb and disk; GNSS scintillation; radio occultation; S4 index

Inferring thermospheric composition from ionogram profiles: a calibration with the TIMED spacecraft

Scott, Christopher; Jones, Shannon; Barnard, Luke;

Published by:       Published on:

YEAR: 2021     DOI:

The Impact of Assimilating Ionosphere and Thermosphere Observations on Neutral Temperature Improvement: Observing System Simulation Experiments Using EnKF

Accurate specification of the thermosphere states is crucial to the low Earth orbit satellite operation. In this work, the impact of different ionosphere and thermosphere observing systems on the improvement of neutral temperature of the data assimilation model has been investigated by a series of observing system simulation experiments. The selected observations include the Global Navigation Satellite System total electron content (e.g., MIT vertical total electron content [VTEC]) and the daytime Global-scale Observations o ...

He, Jianhui; Yue, Xinan; Ren, Zhipeng;

Published by: Space Weather      Published on:

YEAR: 2021     DOI: 10.1029/2021SW002844

PROBA2 LYRA Occultations: Thermospheric Temperature and Composition, Sensitivity to EUV Forcing, and Comparisons With Mars

A method for retrieving temperature and composition from 150 to 350 km in Earth s thermosphere using total number density measurements made via extreme ultraviolet (EUV) solar occultations by the Project for OnBoard Autonomy 2/Large Yield Radiometer (PROBA2/LYRA) instrument is presented. Systematic and random uncertainties are calculated and found to be less than 5\% for the temperature measurements and 5\%–20\% for the composition measurements. Regression coefficients relating both temperature and the [O]/[N2] abundance r ...

Thiemann, Edward; Dominique, Marie;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029262

comparative planetology; EUV; occultations; space weather; thermosphere

The Thermospheric Column O/N2 Ratio

More than 2 decades ago, D. J. Strickland and colleagues proposed use of the O/N2 column number density ratio as a new geophysical quantity to interpret thermospheric processes recorded in far ultraviolet (FUV) images of the Earth. This concept has enabled multiple advances in understanding the global behavior of Earth s thermosphere. Nevertheless, confusion remains about the conceptual meaning of the column density ratio, and in the application of this integral quantity. This is so even though it is now a key thermospheric ...

Meier, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA029059

disk algorithm; far UV remote sensing; GUVI; ICON; N2 LBH bands; Oxygen 135.6 nm

Transpolar Arcs During a Prolonged Radial Interplanetary Magnetic Field Interval

Transpolar arcs (TPAs) are believed to predominantly occur under northward interplanetary magnetic field (IMF) conditions with their hemispheric asymmetry controlled by the Sun-Earth (radial) component of the IMF. In this study, we present observations of TPAs that appear in both the northern and southern hemispheres even during a prolonged interval of radially oriented IMF. The Defense Meteorological Satellite Program (DMSP) F16 and the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellites observed T ...

Park, Jong-Sun; Shi, Quan; Nowada, Motoharu; Shue, Jih-Hong; Kim, Khan-Hyuk; Lee, Dong-Hun; Zong, Qiu-Gang; Degeling, Alexander; Tian, An; Pitkänen, Timo; Zhang, Yongliang; Rae, Jonathan; Hairston, Marc;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029197

radial IMF; solar wind-magnetosphere-ionosphere coupling; transpolar arc

The Ionosphere at Middle and Low Latitudes Under Geomagnetic Quiet Time of December 2019

The ionospheric electron density shows remarkable day-to-day variability due to solar radiance, geomagnetic activity and lower atmosphere forcing. In this report, we investigated the ionospheric variations at middle and low latitudes during a period under geomagnetic quiet time (Kpmax = 1.7) from November 30 to December 8, 2019. During the quiescent period, the ionosphere is not undisturbed as expected in the Asian-Australian and the American sectors. Total electron content (TEC) has multiple prominent enhancements at middle ...

Kuai, Jiawei; Li, Qiaoling; Zhong, Jiahao; Zhou, Xu; Liu, Libo; Yoshikawa, Akimasa; Hu, Lianhuan; Xie, Haiyong; Huang, Chaoyan; Yu, Xumin; Wan, Xin; Cui, Jun;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028964

low-latitude electric fields; the ionosphere variations in solar minimum; the ionospheric day-to-day variations; the ionospheric disturbance; the ionospheric variations; topside ionosphere

Storm-Time Neutral Composition Changes in the Upper Atmosphere

During geomagnetic storms, energy inputs, such as particle precipitation and Joule heating from the magnetosphere and solar wind, create significant disturbances in the upper atmosphere in the form of changes in the thermospheric density and temperature and, more important, composition, such as O/N 2 column density ratio, nitric oxide (NO) density, and atomic nitrogen (N) density. The composition changes control the ionosphere and have a feedback effect on thermospheric temperature and density due to a cooling effect of enha ...

Zhang, Yongliang; Paxton, Larry;

Published by:       Published on:

YEAR: 2021     DOI: 10.1002/9781119815631.ch7

far ultraviolet observations; storm-time neutral composition changes; thermospheric nitric oxide variations; traveling atmospheric disturbance; traveling ionosphere disturbance; upper atmosphere

The Northward IMF Magnetosphere

The manner in which the Earth s magnetosphere responds to the solar wind is highly dependent upon the orientation of the interplanetary magnetic field (IMF), particularly the north–south (B Z ) component. As most auroral and geomagnetic activity occurs when the IMF is southward (or weakly northward, but dominated by the dawn–dusk [B Y ] component), it is perhaps unsurprising that these conditions have received the most attention. However, when the IMF is more strongly northward (B Z \textgreater 0 and B Z \textgreater \t ...

Fear, Robert;

Published by:       Published on:

YEAR: 2021     DOI: 10.1002/9781119815624.ch19

auroral response; Earth s magnetosphere; geomagnetic activity; interplanetary magnetic field; magnetospheric dynamics; solar wind-magnetosphere coupling

First Results From the Retrieved Column O/N2 Ratio From the Ionospheric Connection Explorer (ICON): Evidence of the Impacts of Nonmigrating Tides

In near-Earth space, variations in thermospheric composition have important implications for thermosphere-ionosphere coupling. The ratio of O to N2 is often measured using far-UV airglow observations. Taking such airglow observations from space, looking below the Earth s limb allows for the total column of O and N2 in the ionosphere to be determined. While these observations have enabled many previous studies, determining the impact of nonmigrating tides on thermospheric composition has proved difficult, owing to a small con ...

England, Scott; Meier, R.; Frey, Harald; Mende, Stephen; Stephan, Andrew; Krier, Christopher; Cullens, Chihoko; Wu, Yen-Jung; Triplett, Colin; Sirk, Martin; Korpela, Eric; Harding, Brian; Englert, Christoph; Immel, Thomas;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029575

airglow; atmospheric composition; Atmospheric tides; thermosphere

First Look at a Geomagnetic Storm With Santa Maria Digisonde Data: F Region Responses and Comparisons Over the American Sector

Santa Maria Digisonde data are used for the first time to investigate the F region behavior during a geomagnetic storm. The August 25, 2018 storm is considered complex due to the incidence of two Interplanetary Coronal Mass Ejections and a High-Speed Solar Wind Stream (HSS). The F 2 layer critical frequency (f o F 2) and its peak height (h m F 2) collected over Santa Maria, near the center of the South American Magnetic Anomaly (SAMA), are compared with data collected from Digisondes installed in the Northern (NH) and Southe ...

Moro, J.; Xu, J.; Denardini, C.; Resende, L.; Neto, P.; Da Silva, L.; Silva, R.; Chen, S.; Picanço, G.; Carmo, C.; Liu, Z.; Yan, C.; Wang, C.; Schuch, N.;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028663

Digisonde; Equatorial ionization anomaly; F-region; Ionospheric storm; SAMA; space weather

Extreme Positive Ionosphere Storm Triggered by a Minor Magnetic Storm in Deep Solar Minimum Revealed by FORMOSAT-7/COSMIC-2 and GNSS Observations

This study examines an unexpected and extreme positive ionospheric response to a minor magnetic storm on August 5, 2019 by using global ionosphere specification (GIS) 3D electron density profiles obtained by assimilating radio occultation total electron content (TEC) measurements of the recently launched FORMOSAT-7/COSMIC-2 satellites, and ground-based global navigation satellite system (GNSS) TEC. The results reveal ∼300\% enhancement of equatorial ionization anomaly (EIA) crests, appearing over 200–300 km altitudes, an ...

Rajesh, P.; Lin, C.; . Y. Lin, C; Chen, C.; . Y. Liu, J; Matsuo, T.; Chen, S.; Yeh, W.; . Y. Huang, C;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028261

FORMOSAT-7/COSMIC-2; Global Ionospheric Specification; ionospheric data assimilation; ionospheric response to magnetic storm; magnetosphere-ionosphere coupling; minor magnetic storm

Subauroral Flow Channel Structures and Auroral Undulations Triggered by Kelvin-Helmholtz Waves

We investigate Kelvin-Helmholtz (K-H) waves on/near the magnetopause and surface waves near the plasmapause—in the outer region of the plasmasphere: in the hot zone—by utilizing multi-instrument/satellite observations. Our main aim is to study how the K-H waves and the K-H instability mechanisms impacted the subauroral and auroral regions during the geomagnetic storms of May 27–29 and July 16, 2017. For the subauroral region, we specify the structured flows as Sub-Auroral Polarization Streams Wave Structures (SAPS-WS) ...

Horvath, Ildiko; Lovell, Brian;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029144

ASAID/SAPS/SAPS-WS; auroral undulations; hot zone; K-H instability

Solar Origins of August 26, 2018 Geomagnetic Storm: Responses of the Interplanetary Medium and Equatorial/Low-Latitude Ionosphere to the Storm

This study investigates the solar origins of August 26, 2018 geomagnetic storm and the responses of the interplanetary medium and equatorial/low-latitude ionosphere to it. We used a multiinstrument approach, with observations right from the solar surface to the Earth. Our results showed that the G3 geomagnetic storm of August 26, 2018 was initiated by a solar filament eruption of August 20, 2018. The storm was driven by an aggregation of weak Coronal Mass Ejection (CME) transients and Corotating Interaction Regions/High Spee ...

Akala, A.; Oyedokun, O.; Amaechi, P.; Simi, K.; Ogwala, A.; Arowolo, O.;

Published by: Space Weather      Published on:

YEAR: 2021     DOI: 10.1029/2021SW002734

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