scholarly journals Climatology of Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) Observed with GPS Networks in the North African Region

2020 ◽  
Author(s):  
Temitope Seun Oluwadare ◽  
Norbert Jakowski ◽  
Cesar E. Valladares ◽  
Andrew Oke-Ovie Akala ◽  
Oladipo E. Abe ◽  
...  
Keyword(s):  
Occurrence Rate ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
North African ◽  
African Region ◽  
Occurrence Time ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
The North ◽  
June Solstice

Abstract We present for the first time the climatology of medium-scale traveling ionospheric disturbances (MSTIDs) by using Global Positioning System (GPS) receiver networks on geomagnetically quiet days (Kp ≤ 3) over the North African region during 2008-2016. The ionospheric Total Electron Content (TEC) were estimated from the dual-frequency GPS measurements, and the TEC perturbations (dTEC) data were derived from the estimated TEC data. We focused on the TEC perturbations (dTEC) associated MSTIDs and statistically analyzed its characteristics, occurrence rate, diurnal and seasonal behavior as well as the interannual dependence. The results show that MSTID is a local and seasonal dependence. The results also show that MSTIDs predominantly propagates towards the South (equatorward). The daytime and nighttime MSTIDs increase with solar activity, and its event period is (12 ≤ period ≤ 53 mins), while the dominant amplitude is (0.08 ≤ amp ≤ ~1.5 dTECU). The MSTIDs propagation velocity is dominantly higher at the daytime than nighttime. The study also shows that the disturbance occurrence time is more frequent within the hours of (1200 - 1600 LT), and (1000 - 1400 LT) in December solstice at daytime for stations located in the Northwest (NW) and Northeast (NE) part of the African region, respectively. While at the nighttime, the MSTIDs also exhibits variability in disturbance occurrence time around (NW: 2100–0200 LT) and (NE: 1900–0200 LT) in June solstice, but get extended to March equinox during solar maximum (2014). The mean phase velocity in daytime MSTIDs is higher than the nighttime in every season, except during June solstice.

scholarly journals Climatology of Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) Observed with GPS Networks in the North African Region

2021 ◽  
Author(s):  
Temitope Seun Oluwadare ◽  
Norbert Jakowski ◽  
Cesar E. Valladares ◽  
Andrew Oke-Ovie Akala ◽  
Oladipo E. Abe ◽  
...  
Keyword(s):  
Occurrence Rate ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
North African ◽  
African Region ◽  
Occurrence Time ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
The North ◽  
June Solstice

Abstract We present for the first time the climatology of medium-scale traveling ionospheric disturbances (MSTIDs) by using Global Positioning System (GPS) receiver networks on geomagnetically quiet days (Kp ≤ 3) over the North African region during 2008-2016. The ionospheric Total Electron Content (TEC) were estimated from the dual-frequency GPS measurements, and the TEC perturbations (dTEC) data were derived from the estimated TEC data. We focused on the TEC perturbations (dTEC) associated MSTIDs and statistically analyzed its characteristics, occurrence rate, diurnal and seasonal behavior as well as the interannual dependence. The results show that MSTID is a local and seasonal dependence. The results also show that MSTIDs predominantly propagates towards the South (equatorward). The daytime and nighttime MSTIDs increase with solar activity, and its event period is (12 ≤ period ≤ 53 mins), while the dominant amplitude is (0.08 ≤ amp ≤ ~1.5 dTECU). The MSTIDs propagation velocity is dominantly higher at the daytime than nighttime. The study also shows that the magnitude of MSTIDs is higher at the northwest (NW) when compared with northeast (NE), and the disturbance occurrence time is more frequent within the hours of (1200 - 1600 LT), and (1000 - 1400 LT) in December solstice at daytime for stations located in the NW and NE part of the African region, respectively. While at the nighttime, the MSTIDs also exhibits variability in disturbance occurrence time around (NW: 2100 - 0200 LT) and (NE: 1900 - 0200 LT) in June solstice, but get extended to March equinox during solar maximum (2014). The mean phase velocity in daytime MSTIDs is higher than the nighttime in every season, except during June solstice.

scholarly journals Climatology of Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) Observed with GPS Networks in the North African Region

2020 ◽  
Author(s):  
Temitope Seun Oluwadare ◽  
Norbert Jakowski ◽  
Cesar E. Valladares ◽  
Andrew Oke-Ovie Akala ◽  
Oladipo E. Abe ◽  
...  
Keyword(s):  
Solar Activity ◽  
Occurrence Rate ◽  
Ionospheric Disturbances ◽  
North African ◽  
African Region ◽  
Occurrence Time ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
The North ◽  
June Solstice

Abstract We present for the first time the climatology of medium-scale traveling ionospheric disturbances (MSTIDs) by using Global Positioning System (GPS) receiver networks on geomagnetically quiet days (Kp ≤ 3) over the North African region during 2008-2016. The ionospheric Total Electron Content (TEC) were estimated from the dual-frequency GPS measurements, and the TEC perturbations (dTEC) data were derived from the estimated TEC data. We focused on the TEC perturbations (dTEC) associated with medium-scale traveling ionospheric disturbances (MSTIDs) and statistically analyzed the MSTIDs characteristics, occurrence rate, diurnal and seasonal behavior as well as the interannual dependence. The oscillating wave-like pattern of MSTIDs showed a local and seasonal dependence of nighttime and daytime. The results showed that MSTIDs propagation direction is predominantly towards the South (equatorward), MSTIDs event period is (12 ≤ period ≤ 53 mins), and dominant amplitude (0.08 ≤ amp ≤ ~1.5 TECU), with a propagation velocity higher at daytime than nighttime. The amplitudes of the MSTIDs increase with solar activity. The study reveals that the spatio-temporal variation of MSTIDs depends on local time and solar activity. The study also shows that the disturbance occurrence time is dominant within the hours of (1200–1600 LT), and (1000–1400 LT) in December solstice at daytime for stations located in the Northwest (NW) and Northeast (NE) part of the African region, respectively. While at the nighttime, the MSTIDs exhibits variability in disturbance occurrence time around (NW: 2100–0200 LT) and (NE: 1900–0200 LT) in June solstice, but get extended to March equinox during solar maximum (2014). The mean phase velocity in daytime MSTIDs is higher than the nighttime in every season, except during June solstice. The study revealed that atmospheric gravity waves (AGWs) control the daytime MSTIDs occurrence for a selected day.

scholarly journals Climatology of Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) Observed with GPS Networks in the North African Region

2020 ◽  
Author(s):  
Temitope Seun Oluwadare ◽  
Norbert Jakowski ◽  
Cesar E. Valladares ◽  
Andrew Oke-Ovie Akala ◽  
Oladipo E. Abe ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Occurrence Rate ◽  
Ionospheric Disturbances ◽  
North African ◽  
African Region ◽  
Atmospheric Gravity Waves ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
The North ◽  
Atmospheric Gravity

Abstract We present for the first time the climatology of medium-scale traveling ionospheric disturbances (MSTIDs) by using Global Positioning System (GPS) receiver networks on geomagnetically quiet days (Kp ≤ 3) over the North African region during 2008-2016. The MSTIDs appear frequently as oscillating waves or wave-like structures in electron density induced by the passage of Atmospheric Gravity Waves (AGW) propagating through the neutral atmosphere and consequently, causing fluctuation in the ionospheric Total Electron Content (TEC). The TEC perturbations (dTEC) data are derived from dual frequency GPS-measurements. We have statistically analyzed the MSTIDs characteristics, occurrence rate, seasonal behavior as well as the interannual dependence. The results show a local and seasonal dependence of nighttime and daytime MSTIDs. The propagation direction is predominantly towards the South (equatorward), MSTIDs event period is (12 ≤ period ≤ 53 mins), and dominant amplitude (0.08 ≤ amp ≤ ~1.5 TECU), with a propagation velocity higher at daytime than nighttime. The amplitudes of the MSTIDs increase with solar activity. The local MSTIDs Spatio-temporal heat reveals variability in disturbance occurrence time, but seems to be dominant within the hours of (Northwest: 1200–1600 LT) and (Northeast: 1000–1400 LT) in December solstice during daytime, and around (NW: 2100–0200 LT) and (NE: 1900–0200 LT) in June solstice, but get extended to March equinox during solar maximum (2014) during the nighttime. The time series of MSTIDs regional distribution map is also generated. Atmospheric gravity waves (AGW) seems to be responsible for the daytime MSTIDs occurrence.

scholarly journals Climatology of Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) Observed with GPS Networks in the North African Region

2020 ◽  
Author(s):  
Temitope Seun Oluwadare ◽  
Norbert Jakowski ◽  
Cesar E. Valladares ◽  
Andrew Oke-Ovie Akala ◽  
Oladipo E. Abe ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Ionospheric Disturbances ◽  
North African ◽  
African Region ◽  
Occurrence Time ◽  
The North ◽  
June Solstice ◽  
The Hours ◽  
December Solstice ◽  
Atmospheric Gravity

Abstract We present for the first time the climatology of medium-scale traveling ionospheric disturbances (MSTIDs) by using Global Positioning System (GPS) receiver networks on geomagnetically quiet days (Kp ≤ 3) over the North African region during 2008-2016. The MSTIDs appear frequently as oscillating waves or wave-like structures in electron density induced by the passage of Atmospheric Gravity Waves (AGW) propagating through the neutral atmosphere and consequently, causing fluctuation in the ionospheric Total Electron Content (TEC). The TEC perturbations (dTEC) data are derived from dual frequency GPS-measurements. We have statistically analyzed the occurrence rate, diurnal and seasonal behavior as well as the annual MSTID occurrence characteristics. The results show a local and latitude dependence of nighttime and daytime MSTIDs. The propagation direction is predominantly towards the South (equatorward), MSTIDs event period is (10 ≤ period ≤ 43 mins), and amplitude (0.08 ≤ amp ≤ ~5.0 TECU), with a velocity higher at nighttime than daytime. The amplitudes for daytime and nighttime MSTIDs increase with solar activity. On the average, the local MSTIDs Spatio-temporal heat map for the Mid-latitude reveals variability in disturbance occurrence time to be dominant within the hours of 0900 - 1600 LT in December solstice (winter) and 1900–0400 LT in June solstice (summer) for daytime and nighttime respectively. While the low latitude reveals the disturbance occurrence time to be dominant within the hours of 1100 - 1800 LT in December solstice (winter) and 2000–0200 LT in equinox months and June solstice (summer) for daytime and nighttime respectively. The time series MSTIDs regional distribution map is also generated. Atmospheric gravity waves (AGW) might be responsible for the excitation mechanism for daytime MSTIDs.

scholarly journals Climatology of Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) Observed with GPS Networks in the North African Region

2020 ◽  
Author(s):  
Temitope Seun Oluwadare ◽  
Norbert Jakowski ◽  
Cesar E. Valladares ◽  
Andrew Oke-Ovie Akala ◽  
Oladipo E. Abe ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Ionospheric Disturbances ◽  
North African ◽  
African Region ◽  
Occurrence Time ◽  
The North ◽  
June Solstice ◽  
The Hours ◽  
December Solstice ◽  
Atmospheric Gravity

Abstract We present for the first time the climatology of medium-scale traveling ionospheric disturbances (MSTIDs) by using Global Positioning System (GPS) receiver networks on geomagnetically quiet days (Kp ≤ 3) over the North African region during 2008-2016. The MSTIDs appear frequently as oscillating waves or wave-like structures in electron density induced by the passage of Atmospheric Gravity Waves (AGW) propagating through the neutral atmosphere and consequently, causing fluctuation in the ionospheric Total Electron Content (TEC). The TEC perturbations (dTEC) data are derived from dual frequency GPS-measurements. We have statistically analyzed the occurrence rate, diurnal and seasonal behavior as well as the annual MSTID occurrence characteristics. The results show a local and latitude dependence of nighttime and daytime MSTIDs. The propagation direction is predominantly towards the South (equatorward), MSTIDs event period is (10 ≤ period ≤ 43 mins), and amplitude (0.08 ≤ amp ≤ ~5.0 TECU), with a velocity higher at nighttime than daytime. The amplitudes for daytime and nighttime MSTIDs increase with solar activity. On the average, the local MSTIDs Spatio-temporal heat map for the Mid-latitude reveals variability in disturbance occurrence time to be dominant within the hours of 0900 - 1600 LT in December solstice (winter) and 1900–0400 LT in June solstice (summer) for daytime and nighttime respectively. While the low latitude reveals the disturbance occurrence time to be dominant within the hours of 1100 - 1800 LT in December solstice (winter) and 2000–0200 LT in equinox months and June solstice (summer) for daytime and nighttime respectively. The time series MSTIDs regional distribution map is also generated. Atmospheric gravity waves (AGW) might be responsible for the excitation mechanism for daytime MSTIDs.

scholarly journals GPS observations of medium-scale traveling ionospheric disturbances over Europe

2013 ◽  
Vol 31 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Y. Otsuka ◽  
K. Suzuki ◽  
S. Nakagawa ◽  
M. Nishioka ◽  
K. Shiokawa ◽  
...  
Keyword(s):  
Electric Field ◽  
Gravity Waves ◽  
Occurrence Rate ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Total Electron ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
Oscillating Electric Field ◽  
Dip Angle

Abstract. Two-dimensional structures of medium-scale traveling ionospheric disturbances (MSTIDs) over Europe have been revealed, for the first time, by using maps of the total electron content (TEC) obtained from more than 800 GPS receivers of the European GPS receiver networks. From statistical analysis of the TEC maps obtained 2008, we have found that the observed MSTIDs can be categorized into two groups: daytime MSTID and nighttime MSTID. The daytime MSTID frequently occurs in winter. Its maximum occurrence rate in monthly and hourly bin exceeds 70% at lower latitudes over Europe, whereas it is approximately 45% at higher latitudes. Since most of the daytime MSTIDs propagate southward, we speculate that they could be caused by atmospheric gravity waves in the thermosphere. The nighttime MSTIDs also frequently occur in winter but most of them propagate southwestward, in a direction consistent with the theory that polarization electric fields play an important role in generating the nighttime MSTIDs. The nighttime MSTID occurrence rate shows distinct latitudinal difference: The maximum of the occurrence rate in monthly and hourly bin is approximately 50% at lower latitudes in Europe, whereas the nighttime MSTID was rarely observed at higher latitudes. We have performed model calculations of the plasma density perturbations caused by a gravity wave and an oscillating electric field to reproduce the daytime and nighttime MSTIDs, respectively. We find that TEC perturbations caused by gravity waves do not show dip angle dependencies, while those caused by the oscillating electric field have a larger amplitude at lower latitudes. These dip angle dependencies of the TEC perturbation amplitude could contribute to the latitudinal variation of the MSTID occurrence rate. Comparing with previous studies, we discuss the longitudinal difference of the nighttime MSTID occurrence rate, along with the E- and F-region coupling processes. The seasonal variation, of the nighttime MSTID occurrence rate in Europe, is not consistent with the theory that the longitudinal and seasonal variations of the nighttime MSTID occurrence could be attributed to those of the Es layer occurrence.

scholarly journals Solar activity dependence of medium-scale traveling ionospheric disturbances using GPS receivers in Japan

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Yuichi Otsuka ◽  
Atsuki Shinbori ◽  
Takuya Tsugawa ◽  
Michi Nishioka
Keyword(s):  
Solar Activity ◽  
Phase Velocity ◽  
Gravity Waves ◽  
Occurrence Rate ◽  
High Solar Activity ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances ◽  
Activity Dependence

AbstractIn order to reveal solar activity dependence of the medium-scale traveling ionospheric disturbances (MSTIDs) at midlatitudes, total electron content (TEC) data obtained from a Global Positioning System (GPS) receiver network in Japan during 22 years from 1998 to 2019 were analyzed. We have calculated the detrended TEC by subtracting the 1-h running average from the original TEC data for each satellite and receiver pair, and made two-dimensional TEC maps of the detrended TEC with a spatial resolution of 0.15° × 0.15° in longitude and latitude. We have investigated MSTID activity, defined as $$\delta I/\overline{I}$$ δ I / I ¯ , where $$\delta I$$ δ I and $$\overline{I}$$ I ¯ are standard deviation of the detrended TEC and the average vertical TEC within the area of 133.0°–137.0° E and 33.0°–37.0° N for 1 h, respectively. From each 2-h time series of the detrended TEC data within the same area as the MSTID activity, auto-correlation functions (ACFs) of the detrended TEC were calculated to estimate the horizontal propagation velocity and direction of the MSTIDs. Statistical results of the MSTID activity and propagation direction of MSTIDs were consistent with previous studies and support the idea that daytime MSTIDs could be caused by atmospheric gravity waves, and that nighttime MSTIDs were caused by electro-dynamical forces, such as the Perkins instability. From the current long-term observations, we have found that the nighttime MSTID activity and occurrence rate increased with decreasing solar activity. For the daytime MSTID, the occurrence rate increased with decreasing solar activity, whereas the MSTID activity did not show distinct solar activity dependence. These results suggest that the secondary gravity waves generated by dissipation of the primary gravity waves propagating from below increase under low solar activity conditions. The mean horizontal phase velocity of the MSTIDs during nighttime did not show a distinct solar activity dependence, whereas that during daytime showed an anticorrelation with solar activity. The horizontal phase velocity of the daytime MSTIDs was widely distributed from 40 to 180 m/s under high solar activity conditions, whereas it ranged between 80 and 200 m/s, with a maximum occurrence at 130 m/s under low solar activity conditions, suggesting that gravity waves with low phase velocity could be dissipated by high viscosity in the thermosphere under low solar activity conditions.

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).

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