Longitudinal Asymmetry of the Occurrence of the Plasma Irregularities over African Low-Latitude Region

Abe, Oladipo E.; Rabiu, Babatunde; Radicella, S. M.

doi:10.1007/s00024-018-1920-z

Cited by 8 publications

(8 citation statements)

References 58 publications

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“…Figure 5 shows a higher magnitude of MSTIDs at certain latitudes, this is in line with Abe et al (2018) Figure 5 Two-dimensional maps of MSTIDs over North Africa at 1000 to * 1400 UT on 7 th March, 2010 (DOY 066).…”

Section: Two-dimensional Observation Of Mstids Oversupporting

confidence: 81%

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

Oluwadare

Jakowski

Valladares

et al. 2022

Pure Appl. Geophys.

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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 result reveals that occurrence of MSTIDs increases with solar activity. It also shows that MSTIDs predominantly propagates towards the South (equatorward). The MSTIDs event period is (12 ≤ period ≤ 53 min), while the dominant peak-to-peak amplitude is (0.08 ≤ amp ≤ ~ 1.5 dTECU). The study also shows that the amplitude of MSTIDs is higher at the northwest (Lat: ~ 32° N to ~ 38° N, Long: ~ 2° W to ~ 15° W) when compared with northeast (Lat: ~ 28° N to ~ 38° N, Long: ~ 23° E to ~ 40° E), 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 northwest and northeast part of the African region, respectively. While at the nighttime, the MSTIDs also exhibits variability in disturbance occurrence time around (northwest: 2100–0200 LT) and (northeast: 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.

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Section: Two-dimensional Observation Of Mstids Oversupporting

confidence: 81%

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

Oluwadare

Jakowski

Valladares

et al. 2022

Pure Appl. Geophys.

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“…However, the magnitude of MSTIDs propagating the NW is higher compared to NE. This is similar to Abe et al 2018 that decribed the logitudinal asymmetry of equatorial plasma irregularities over African equatorial region. the daytime during 1100 -1600 LT, and 0900 -1400 LT at NW and NE, respectively during the March equinox and December solstice, respectively.…”

Section: Discussionsupporting

confidence: 85%

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

Oluwadare

Jakowski

Valladares

et al. 2021

Preprint

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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.

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“…According to the previous studies (e.g., Fejer et al, 1999), the basic mechanism for the formation and evolution of the ionospheric irregularities is the Rayleigh-Taylor instability and the E × B instability (Abalde et al, 2009;Deng et al, 2013). As mentioned by Ram et al (2006) and Abalde et al (2009), some other processes that also contribute to the onset and evolution of the ionospheric irregularities are (1) the evening enhancement in the eastward electric field (Abdu et al, 2008) and rapid uplifting of the equatorial F region around sunset period (Fejer et al, 1999;Hoang et al, 2010;Sahai et al, 2000), (2) a sharp gradient at the base of the F region (Cervera & Thomas, 2006;Kelley, 1989), (3) a simultaneous decay of the E layer conductivity at both ends of the field line (Tsunoda, 1985), and (4) the transequatorial meridional neutral winds (Abe et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Morphological Features of Ionospheric Scintillations During High Solar Activity Using GPS Observations Over the South American Sector

et al. 2020

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The main objective of this study is to investigate the ionospheric irregularities observed by Global Positioning System-total electron content (GPS-TEC) receivers during the high solar activity years of 2013 and 2014 at different stations in the equatorial and low-latitude regions in the South American sector. The ionospheric parameters used in this investigation are the TEC, the rate of change of the TEC index (ROTI), and the amplitude scintillation index (S4). In the South American sector, the ROTI and S4 indices showed that the ionospheric irregularities have an annual variation with maximum occurrence from September to April, between 20:00 LT and 02:00 LT, and no occurrence from May to August. Also, strong phase fluctuations (ROTI >1) are observed over South America at 19 LT in October and November. Morlet wavelet analysis of ROTI and S4 showed that planetary wave-scale periods ranging from 2 to 8 days are predominant during September-March at 20-02 LT in South America. In addition, using a keogram it was possible to evaluate the distance between adjacent ionospheric plasma depletions, and this result is presented and discussed. The longitudinal distances between adjacent bubbles vary around~600-1000 km, which is larger than values reported in most previous studies.

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Longitudinal Asymmetry of the Occurrence of the Plasma Irregularities over African Low-Latitude Region

Cited by 8 publications

References 58 publications

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

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

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

Morphological Features of Ionospheric Scintillations During High Solar Activity Using GPS Observations Over the South American Sector

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