Investigation of Nighttime MSTIDS Observed by Optical Thermosphere Imagers at Low Latitudes: Morphology, Propagation Direction, and Wind Filtering

Figueiredo, C. A. O. B.; Takahashi, H.; Wrasse, C. M.; Otsuka, Yuichi; Shiokawa, K.; Barros, Diego

doi:10.1029/2018ja025438

Cited by 33 publications

(41 citation statements)

References 73 publications

(215 reference statements)

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“…We estimated their horizontal wavelength, phase speed and period to be ~ 254 ± 7 km, 190 ± 43 m/s, and 22 min, respectively. The propagation characteristics of these bands is somewhat similar to those of the MSTIDs reported earlier (Garcia et al, ; Shiokawa et al, ; Kubota et al, ; Fukushima et al, ; Shiokawa et al, ; Narayanan et al, ; Figueiredo et al, ). Table summarizes the propagation characteristics of MSTIDs reported in few reports along with that noted in this present study.…”

Section: Observationssupporting

confidence: 85%

Rare Occurrence of Off‐Equatorial Edge Initiating and Equatorward Surging Plasma Depletions Observed in OI 630‐nm Imaging

Parihar

2019

JGR Space Physics

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Usual depletions in the Northern Hemisphere form a tree fork junction feature near the south (i.e., toward the equator) in all-sky airglow images, and its branches surge toward the north (i.e., poleward). We report in this paper unusual airglow depletions in OI 630.0-nm imaging over India that surged equatorward and formed an inverted tree fork junction feature on 3 January 2011. Airglow images showed faint signatures of medium-scale traveling ionospheric disturbances in the beginning that were east-west aligned and propagated toward equator. Within 06 to 18 min of its passing, turbulent structures were noted in the field of view, and two depleted patches appeared out of low airglow background over the off-equatorial edge. The apex height of the associated geomagnetic flux tubes varied from~1,400 to 1,600 km. Later, these dark regions intensified and surged equatorward while drifting slowly toward west. While remaining almost steady, one of them further intensified and continued to surge equatorward. The second dark patch got linked up with another isolated depletion to form an elongated depleted feature. Next, the southern end of this attached feature surged equatorward. When two depletions were well formed, an inverted tree fork junction was noticeable. During this time, the equatorward motion of the equatorial ionization anomaly structure is also seen. To the best of our knowledge, this is the first imaging observation of an inverted tree fork junction feature and brings out the unknown facets of ionospheric irregularities.Plain Language Summary Usual depletions form a tree fork junction feature near the equatorial edge in all-sky airglow images; its branches surge poleward. On 3 January 2011, unusual depletions were noted over India that surged equatorward and formed an inverted tree fork junction. We present an independent usual depletion event. Such an inverted feature has been not reported earlier to the best of our knowledge and brings out the unknown facets of ionospheric irregularities.

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Section: Observationssupporting

confidence: 85%

Rare Occurrence of Off‐Equatorial Edge Initiating and Equatorward Surging Plasma Depletions Observed in OI 630‐nm Imaging

Parihar

2019

JGR Space Physics

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“…In ionospheric F region, medium‐scale traveling ionospheric disturbances (MSTIDs) that propagate southwestward with phase fronts aligned in the NW‐SE direction in Northern Hemisphere were frequently detected at middle latitude (e.g., Ding et al, ; Figueiredo et al, ; Saito et al, ; Zhou et al, ). The electrodynamic Perkins instability (Perkins, ) can explain the preferred alignment of frontal structures of MSTIDs.…”

Section: Introductionmentioning

confidence: 99%

Coupling Between E Region Quasi‐Periodic Echoes and F Region Medium‐Scale Traveling Ionospheric Disturbances at Low Latitudes

Xie

Zhao

et al. 2020

JGR Space Physics

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E region quasi-periodic (QP) echoes from a VHF coherent backscatter radar, sporadic E (E s ) layer from a digisonde, and F region medium-scale traveling ionospheric disturbances (MSTIDs) from global navigation satellite systems receivers were simultaneously observed at low latitudes. The results on the night of 3 March 2018 show that the QP echoes in radar height-time intensity maps were clustered into groups, coinciding with the periods of MSTIDs and strong E s layer. The MSTIDs had phase fronts elongating in the northwest-southeast direction and propagated southwestward from middle to low latitudes. Similar to the propagation direction of MSTIDs, the low-latitude E s layers also propagated southwestward. For the QP echoing clusters, a westward drift was seen from the radar multibeam observations. The Doppler velocities of QP echoes show beam dependence, with significantly enhanced positive values (motion away from the radar) in the westernmost beam. Based on a preliminary statistical analysis during the period March-June 2018, it was found that out of a total of 102 nights, there are 32 nights when QP echoes were generated. The simultaneous occurrences of QP echoes and MSTIDs were observed on six nights. We suggest that when the MSTIDs coming from middle latitudes approach low latitudes, the polarization electric fields associated with the MSTIDs could modulate the E region plasma instability producing QP echoes at low latitudes through the E-F region electrodynamic coupling.

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“…The propagation directions during these seasons are different from the results previously observed by (Kotake et al 2007) who studied MSTIDs over Southern California using GPS network, and Fukushima et al observed that nighttime MSTIDs over "São João do Cariri" in the Southern hemisphere exhibited propagation direction towards the north, northeast, northwest, and southeast. Comparison of the nighttime MSTIDs propagation direction results from Kotake et al (2007), Figueiredo et al (2018b), Paulino et al (2016), and the current study shows an indication that location of the different MSTIDs source could possibly influence propagation direction, and that Perkin instability theory does not always play out in nighttime MSTIDs propagation direction. In addition, we may also possibly say that these propagation direction differences may be as a consequences of wind filtering (Figueiredo et al, 2018b).…”

Section: Discussionmentioning

confidence: 57%

“…Comparison of the nighttime MSTIDs propagation direction results from Kotake et al (2007), Figueiredo et al (2018b), Paulino et al (2016), and the current study shows an indication that location of the different MSTIDs source could possibly influence propagation direction, and that Perkin instability theory does not always play out in nighttime MSTIDs propagation direction. In addition, we may also possibly say that these propagation direction differences may be as a consequences of wind filtering (Figueiredo et al, 2018b).…”

Section: Discussionmentioning

confidence: 57%

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

Oluwadare

Jakowski

Valladares

et al. 2020

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 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.

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Investigation of Nighttime MSTIDS Observed by Optical Thermosphere Imagers at Low Latitudes: Morphology, Propagation Direction, and Wind Filtering

Cited by 33 publications

References 73 publications

Rare Occurrence of Off‐Equatorial Edge Initiating and Equatorward Surging Plasma Depletions Observed in OI 630‐nm Imaging

Rare Occurrence of Off‐Equatorial Edge Initiating and Equatorward Surging Plasma Depletions Observed in OI 630‐nm Imaging

Coupling Between E Region Quasi‐Periodic Echoes and F Region Medium‐Scale Traveling Ionospheric Disturbances at Low Latitudes

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

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