Evidence of Mid- and Low-Latitude Nighttime Ionospheric $E$ –$F$ Coupling: Coordinated Observations of Sporadic $E$ Layers, $F$ -Region Field-Aligned Irregularities, and Medium-Scale Traveling Ionospheric Disturbances

2019 ◽  
Vol 57 (10) ◽  
pp. 7547-7557 ◽  
Author(s):  
Yi Liu ◽  
Chen Zhou ◽  
Qiong Tang ◽  
Jian Kong ◽  
Xudong Gu ◽  
...  
Keyword(s):  
Ionospheric Disturbances ◽  
Low Latitude ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
F Region ◽  
Sporadic E Layers ◽  
Sporadic E ◽  
Field Aligned Irregularities

scholarly journals Statistical study of medium-scale traveling ionospheric disturbances in low-latitude ionosphere using an automatic algorithm

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Pin-Hsuan Cheng ◽  
Charles Lin ◽  
Yuichi Otsuka ◽  
Hanli Liu ◽  
Panthalingal Krishanunni Rajesh ◽  
...  
Keyword(s):  
Climate Model ◽  
Geomagnetic Latitude ◽  
Detection Algorithm ◽  
Support Vector ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Low Latitude ◽  
Total Electron ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances

AbstractThis study investigates the medium-scale traveling ionospheric disturbances (MSTIDs) statistically at the low-latitude equatorial ionization anomaly (EIA) region in the northern hemisphere. We apply the automatic detection algorithm including the three-dimensional fast Fourier transform (3-D FFT) and support vector machine (SVM) on total electron content (TEC) observations, derived from a network of ground-based global navigation satellite system (GNSS) receivers in Taiwan (14.5° N geomagnetic latitude; 32.5° inclination), to identify MSTID from other waves or irregularity features. The obtained results are analyzed statistically to examine the behavior of low-latitude MSTIDs. Statistical results indicate the following characteristics. First, the southward (equatorward) MSTIDs are observed almost every day during 0800–2100 LT in Spring and Winter. At midnight, southward MSTIDs are more discernible in Summer and majority of them are propagating from Japan to Taiwan. Second, northward (poleward) MSTIDs are more frequently detected during 1200–2100 LT in Spring and Summer with the secondary peak of occurrence between day of year (DOY) 100–140 during 0000–0300 LT. The characteristics of the MSTIDs are interpreted with additional observations from radio occultation (RO) soundings of FORMOSAT-3/COSMIC as well as modeled atmospheric waves from the high-resolution Whole Atmosphere Community Climate Model (WACCM) suggesting that the nighttime MSTIDs in Summer is likely connected to the atmospheric gravity waves (AGWs).

Numerical Modeling of the Concentric Gravity Wave Seeding of Low-Latitude Nighttime Medium-Scale Traveling Ionospheric Disturbances

2018 ◽  
Vol 45 (13) ◽  
pp. 6390-6399 ◽  
Author(s):  
Min-Yang Chou ◽  
Charles C. H. Lin ◽  
Joseph D. Huba ◽  
Chuan-Ping Lien ◽  
Chia-Hung Chen ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Gravity Wave ◽  
Ionospheric Disturbances ◽  
Low Latitude ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances

scholarly journals Statistical Study of Medium-Scale Traveling Ionospheric Disturbances in Low-Latitude Ionosphere Using an Automatic Algorithm

2020 ◽  
Author(s):  
PinHsuan Cheng ◽  
Charles Lin ◽  
Yuichi Otsuka ◽  
Hanli Liu ◽  
Panthalingal Krishanunni Rajesh ◽  
...  
Keyword(s):  
Climate Model ◽  
Geomagnetic Latitude ◽  
Detection Algorithm ◽  
Support Vector ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Low Latitude ◽  
Total Electron ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances

Abstract This study investigates the medium–scale traveling ionospheric disturbances (MSTIDs) statistically at the low–latitude equatorial ionization anomaly (EIA) region in the northern hemisphere. We apply the automatic detection algorithm including the three-dimensional fast Fourier transform (3-D FFT) and support vector machine (SVM) on total electron content (TEC) observations, derived from a network of ground-based global navigation satellite system (GNSS) receivers in Taiwan (14.5°N geomagnetic latitude; 32.5° inclination), to identify MSTID from other waves or irregularity features. The obtained results are analyzed statistically to examine the behavior of low-latitude MSTIDs. Statistical results indicate the following characteristics. First, the southward (equatorward) MSTIDs are observed almost every day during 0800-2100 LT in Spring and Winter. At midnight, southward MSTIDs are more discernible in Summer and majority of them are propagating from Japan to Taiwan. Second, northward (poleward) MSTIDs are more frequently detected during 1200-2100 LT in Spring and Summer with the secondary peak of occurrence between day of year (DOY) 100-140. The characteristics of the MSTIDs are interpreted with additional observations from radio occultation (RO) soundings of FORMOSAT-3/COSMIC as well as modeled atmospheric waves from the high–resolution Whole Atmosphere Community Climate Model (WACCM) suggesting that the nighttime MSTIDs in Summer is likely connected to the atmospheric gravity waves (AGWs).

Characteristics of daytime medium scale traveling ionospheric disturbances (MSTIDs) as observed by SWARM

2020 ◽  
Author(s):  
Chinmaya Nayak ◽  
Stephan Buchert
Keyword(s):  
Electron Density ◽  
Ionospheric Disturbances ◽  
Magnetic Fluctuations ◽  
Low Latitude ◽  
Plasma Irregularities ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
Spatio Temporal ◽  
Low Latitude Ionosphere ◽  
Rule Out

<p><span>This paper studies the daytime medium scale traveling ionospheric disturbances (MSTIDs) in the mid- and low-latitude ionosphere for a period of nearly half a solar cycle (2014-2019) using SWARM observations. We specifically focus on daytime MSTIDs to rule out any contribution from nighttime plasma irregularities. Fluctuations in electron density are primarily used to identify the MSTIDs. These wave like structures are independently observed in both electron density and magnetic fluctuations, although they do not always show one to one correlation. In most cases, the structures are observed by both satellite ‘A’ and ‘C’, suggesting that their zonal extent is more than 140 km. The study makes an attempt to understand and explain the magnetic conjugate nature of the MSTIDs. To have a better understanding of the dynamics of the MSTIDs, ground based GPS-TEC and ionosonde data has been used on case to case basis, wherever available. Additionally, spatio-temporal statistics of MSTID distribution is presented. </span></p>

scholarly journals Observational evidence of coupling between quasi-periodic echoes and medium scale traveling ionospheric disturbances

2007 ◽  
Vol 25 (10) ◽  
pp. 2185-2194 ◽  
Author(s):  
S. Saito ◽  
M. Yamamoto ◽  
H. Hashiguchi ◽  
A. Maegawa ◽  
A. Saito
Keyword(s):  
Observational Evidence ◽  
Ionospheric Disturbances ◽  
Gps Receiver ◽  
Interferometric Imaging ◽  
Geomagnetic Field Line ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
F Region ◽  
Mu Radar ◽  
E Region

Abstract. We have found that quasi-periodic (QP) echoes in the E region were well defined when medium scale traveling ionospheric disturbances (MSTIDs) in the F region were present. The appearance and disappearance of the MSTIDs observed with the dense GPS receiver network are well correlated with the development and decay of QP echoes observed with the Middle-and-Upper atmosphere (MU) radar. Interferometric imaging of the QP echoes obtained using the MU radar shows that bands of echoing regions aligned northwest to southeast drift southwestward, and their wavefront and propagation direction are the same as those of MSTIDs. This result confirms the expectation of Hysell et al. (2002) who observed band structures in QP echoes by using the MU radar and suggested their relation to MSTIDs. We found observational evidence that the midlatitude E- and F regions are coupled through the geomagnetic field line, although we could not clearly ascertain which of the two regions is the source.

scholarly journals <i>E</i>-region wind-driven electrical coupling of patchy sporadic-<i>E</i> and spread-<i>F</i> at midlatitude

2005 ◽  
Vol 23 (6) ◽  
pp. 2095-2105 ◽  
Author(s):  
S. Shalimov ◽  
C. Haldoupis
Keyword(s):  
Electric Fields ◽  
Electrical Coupling ◽  
Neutral Winds ◽  
Medium Scale ◽  
F Region ◽  
Sporadic E Layers ◽  
Spread F ◽  
Sporadic E ◽  
Electric Fields And Currents

Abstract. This paper investigates the role of neutral winds in the generation of relatively large polarization electric fields across patchy sporadic-E layers, which then map upward to the F region, to create conditions for medium-scale spread-F. The calculations are based on an analytical model that uses the current continuity equation and field-aligned current closures to the F region in order to describe quantitatively a Hall polarization process inside sporadic-E plasma patches during nighttime. In applying this model we use experimentally known values for E and F region, conductances, the ambient electric fields and prevailing neutral winds, in order to estimate the polarization fields that build up inside sporadic-E. It is found that the relatively strong west-southwest neutral winds during summer nighttime can provide the free energy for the generation of sizable polarization electric fields, which have comparable eastward and north-upward components and reach values of several mV/m. Given that the sporadic-E patches have sizes from a few to several tens of kilometers, the polarization fields can map easily to the F region bottomside where they impact ExB plasma uplifts and westward bulk motions, in line with key observational properties of medium-scale spread-F. However, the present simple model needs further development to also include wind forcing of the F region plasma and possible polarization processes inside spread-F. Keywords. Ionosphere (Electric fields and currents; Ionospheric irregularities; Mid-latitude ionosphere)

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