Influence of Zonal Wind Velocity Variation on Equatorial Plasma Bubble Occurrences Over Southeast Asia

Sarudin, I.; Hamid, Nurul Shazana Abdul; Abdullah, Mardina; Buhari, Suhaila M.; Shiokawa, K.; Otsuka, Yuichi; Hozumi, Kornyanat; Jamjareegulgarn, Punyawi

doi:10.1029/2020ja028994

Cited by 9 publications

(3 citation statements)

References 37 publications

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“…The postsunet enhancement of eastward zonal electric field and upward plasma drift due to increased zonal wind and conductivity gradient, known as PRE (Farley et al, 1986;Heelis, 2004;Eccles et al, 2015), provides a favorable condition to facilitate the growth of the R-T instability by causing the postsunset rise (PSSR) of the equatorial F-layer to higher altitudes with lower ionneutral collision frequency (e.g., Fejer et al, 1999;Sarudin et al, 2021). Along this line, some studies suggested that strong vertical plasma drift exceeding certain thresholds seems to conduct a systematic control on the development of EPBs.…”

Section: Prereversal Enhancementmentioning

confidence: 99%

Multi-instrumental analysis of the day-to-day variability of equatorial plasma bubbles

Zhang

Coster

et al. 2023

Front. Astron. Space Sci.

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This paper presents a multi-instrument observational analysis of the equatorial plasma bubbles (EPBs) variation over the American sector during a geomagnetically quiet time period of 07–10 December 2019. The day-to-day variability of EPBs and their underlying drivers are investigated through coordinately utilizing the Global-scale Observations of Limb and Disk (GOLD) ultraviolet images, the Ionospheric Connection Explorer (ICON) in-situ and remote sensing data, the global navigation satellite system (GNSS) total electron content (TEC) observations, as well as ionosonde measurements. The main results are as follows: 1) The postsunset EPBs’ intensity exhibited a large day-to-day variation in the same UT intervals, which was fairly noticeable in the evening of December 07, yet considerably suppressed on December 08 and 09, and then dramatically revived and enhanced on December 10. 2) The postsunset linear Rayleigh-Taylor instability growth rate exhibited a different variation pattern. It had a relatively modest peak value on December 07 and 08, yet a larger peak value on December 09 and 10. There was a 2-h time lag of the growth rate peak time in the evening of December 09 from other nights. This analysis did not show an exact one-to-one relationship between the peak growth rate and the observed EPBs intensity. 3) The EPBs’ day-to-day variation has a better agreement with that of traveling ionospheric disturbances and atmospheric gravity waves signatures, which exhibited relatively strong wavelike perturbations preceding/accompanying the observed EPBs on December 07 and 10 yet relatively weak fluctuations on December 08 and 09. These coordinate observations indicate that the initial wavelike seeding perturbations associated with AGWs, together with the catalyzing factor of the instability growth rate, collectively played important roles to modulate the day-to-day variation of EPBs. A strong seeding perturbation could effectively compensate for a moderate strength of Rayleigh-Taylor instability growth rate and therefore their combined effect could facilitate EPB development. Lacking proper seeding perturbations would make it a more inefficient process for the development of EPBs, especially with a delayed peak value of Rayleigh-Taylor instability growth rate.

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Section: Prereversal Enhancementmentioning

confidence: 99%

Multi-instrumental analysis of the day-to-day variability of equatorial plasma bubbles

Zhang

Coster

et al. 2023

Front. Astron. Space Sci.

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“…Figures 5 and 6 present the seasonal variation of CEJ types in the east and west, respectively. Each figure was complemented with its annual rate that was estimated according to season-Equinox (March-May, September-November), June solstice (June-August), and December solstice (December-February) [32,33] in subplots (a) and (d). Also included are a series of pie charts to represent season dominancy at different solar activity levels.…”

Section: Cej Occurrences Based On Local Times Solar Activity Levels A...mentioning

confidence: 99%

The Variation of Counter-Electrojet Current at the Southeast Asian Sector during Different Solar Activity Levels

et al. 2022

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Studies on counter-electrojet currents (CEJ) using ground data revealed that this current could occur simultaneously among locations that are less than 30° longitude apart. In our work, the symmetricity of CEJ variation between the west and east of Southeast Asia, separated by ~25°, was preliminarily examined according to its types: morning (MCEJ) and afternoon (ACEJ). Since most of the past studies had overlooked the occurrence after dusk, the monitoring period was also extended from 18:00 to 21:00 LT, namely, the post-sunset depletion (PSD). The magnetometer station in Davao, Philippines (DAV) and Langkawi, Malaysia (LKW) were chosen to represent the east and west parts. The EEJ index (i.e., EUEL) over the periods of the solar cycle 24 (2008–2018) was utilized specifically during magnetically quiet days (Kp < 3). As the result, both parts symmetrically showed that MCEJ and ACEJ were positively and negatively correlated with the F10.7 index. Contrarily, MCEJ and ACEJ were asymmetrically prominent in the east and west. CEJ types also varied symmetrically with the season, especially for MCEJ and ACEJ (at high level), prominent during Equinox and J-solstice. Post-sunset depletion (PSD) in both parts was symmetrically solar activity independent, as no correlation with the F10.7 index was observed in the extended observation. PSD that varied symmetrically with season was also solar activity independent, except in the east during Equinox, where it was negatively correlated with the F10.7 index. Our finding also revealed that PSD was prominent during Equinox, except for the high level in the west part.

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“…The changes in the occurrence characteristics of plasma irregularities from one day to the other during quiet and disturbed geomagnetic periods have been discussed in earlier literature [3,9,10]. At the equatorial regions, the zonal wind velocity variation poses a pivotal role in the generation of plasma bubbles which are the primary cause of low-latitude scintillation effects [11]. The zonal irregularities drift velocity is estimated by Vankadara et al [8] using spaced ionospheric monitoring GNSS receiver observations.…”

Section: Introductionmentioning

confidence: 99%

Seasonal Characteristics of Phase Scintillation Observed at UKM Station in Malaysia

Seif,

Panda

2023

J. Phys.: Conf. Ser.

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We present a statistical comparison of the seasonal occurrence of ionospheric phase scintillation in the GPS signals at an equatorial region in Malaysia using the ground-based ionospheric monitoring GPS receiver and space-based radio occultation (RO) measurements. The observations were recorded at UKM (2.55°N, 101.461°E) in Malaysia during 2010 using GPS based scintillation and TEC Monitoring setup (GISTM). The space-based measurements were recorded by the FORMOSAT_3/COSMIC (F_3/C) satellites in 2010. The GPS limb-viewing radio occultation technique is an innovative technique that provides ideal geometry to observe vertical ionospheric structures to detect Equatorial Plasma bubbles (EPBs) and Sporadic E layers (Es). Radio waves throughout the irregular equatorial ionosphere are studied to characterize phase scintillations at the L1 frequency in different seasons. Seasonal characteristics of the GPS phase scintillation show it mainly occurs in the equinox months, particularly during March. The results show similar values as the Radio Occultation (RO) observations over UKM station, which demonstrates that March equinox has the maximum occurrence of scintillations with the appearance of EPBs and during June corresponding to the appearance of the Es layer in the ionosphere. We found seasonal characteristics of phase scintillations obtained from the Ground-based station are consistent with seasonal characteristics of amplitude scintillation that occurred from the space-based measurements. Nevertheless, F3/C RO provided an opportunity for concurrent sounding of EPBs and Es characteristic structures across the globe, unlike other traditional ground-based measurements.

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Influence of Zonal Wind Velocity Variation on Equatorial Plasma Bubble Occurrences Over Southeast Asia

Cited by 9 publications

References 37 publications

Multi-instrumental analysis of the day-to-day variability of equatorial plasma bubbles

Multi-instrumental analysis of the day-to-day variability of equatorial plasma bubbles

The Variation of Counter-Electrojet Current at the Southeast Asian Sector during Different Solar Activity Levels

Seasonal Characteristics of Phase Scintillation Observed at UKM Station in Malaysia

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