Effects of tidal forcing, conductivity gradient, and active seeding on the climatology of equatorial spread <i>F</i> over Kwajalein

Tsunoda, Roland T.; Nguyen, Thi Thanh Hai; Le, Minh Huy

doi:10.1002/2014ja020762

Cited by 27 publications

(29 citation statements)

References 83 publications

(206 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The finding that MREs appear most often around the time of SS E (Tsunoda et al 2015) is consistent with the finding that upwellings are amplified during the PSSR; in fact, the maximum in PSSR rate is centered more or less about SS E (Tsunoda 2009;Tsunoda et al 2015). Occurrences of MREs, in Figure 3, are marked with short, upward-pointing arrows.…”

Section: Ionogram Signaturessupporting

confidence: 84%

Upwelling: a unit of disturbance in equatorial spread F

Tsunoda

2015

Prog. in Earth and Planet. Sci.

120

View full text Add to dashboard Cite

Plasma structure in the nighttime equatorial F layer, often referred to as equatorial spread F (ESF), is not uniformly distributed, either in time or in space. Observations indicate that ESF in the bottomside F layer takes the form of patches; plasma structure within the F layer takes the form of localized plasma depletions, called equatorial plasma bubbles (EPBs), which tend to occur in clusters. Another observed feature is an upwelling, which has been described as a localized, upward modulation of isodensity contours in the bottomside F layer. Interestingly, zonal widths of ESF patches, EPB clusters, and upwellings are similar. Moreover, all display an east-west asymmetry. The objective of this paper is to show, for the first time, that an ESF patch is the bottomside counterpart of an EPB cluster, and that both are products of the electrodynamical process that takes place within an upwelling. The process can be described as having three phases: (1) amplification of upwelling amplitude during the post-sunset rise of the F layer, (2) launching of the first EPB of the evening, from crest of the upwelling, and (3) structuring of plasma within the upwelling. Hence, an upwelling, whose presence is responsible for the formation of ESF patches and EPB clusters, can be envisioned as a unit of disturbance that occurs in the nighttime equatorial ionosphere.

show abstract

Section: Ionogram Signaturessupporting

confidence: 84%

Upwelling: a unit of disturbance in equatorial spread F

Tsunoda

2015

Prog. in Earth and Planet. Sci.

120

View full text Add to dashboard Cite

show abstract

“…Tsunoda et al (2015) examined the characteristics of ESF over Kwajalein and found that the maxima in the ESF occurrence are not aligned with the PRE. The nonalignment between the PRE and the maximum ESF occurrence was considered as indirect evidence that the PRE is not the only parameter that controls the generation of ESF.…”

Section: Seeding Effects On the Generation Of Esfmentioning

confidence: 99%

Effects of the postsunset vertical plasma drift on the generation of equatorial spread F

Huang

2018

Prog Earth Planet Sci

View full text Add to dashboard Cite

Equatorial spread F (ESF) irregularities are caused by plasma instability processes in the equatorial ionosphere and especially related to plasma bubble phenomena in the topside F region. Plasma bubbles result from nonlinear evolution of the Rayleigh-Taylor instability. The prereversal enhancement (PRE) of the postsunset vertical plasma drift increases the height of the equatorial F layer, creating conditions conducive to the growth of the Rayleigh-Taylor instability, and is an important factor that controls the generation of ESF. Three different relationships of the quantitative connection between the PRE and ESF occurrence have been derived. (1) A threshold PRE must be reached for the occurrence of ESF. ESF will be generated when the PRE is larger than the threshold and will not be generated when the PRE is smaller than the threshold. (2) The occurrence probability of ESF increases approximately linearly with the PRE. (3) The occurrence probability of ESF is characterized by a continuous probability distribution as a function of the PRE magnitude. The second and third relationships imply that the PRE can be used to specify the occurrence probability of ESF. This paper will review these relationships and discuss how these relationships are connected to each other. The effects of seeding perturbations on the generation and global distribution of ESF will be briefly discussed.

show abstract

“…The seasonal/longitudinal distribution of the equatorial plasma irregularity has been extensively reported to be strongly correlated with the seasonal variation of the STBA (Abdu et al, 1981;Li et al, 2008;Su et al, 2008). However, a recent study described the significant ESF occurrence during the solstice seasons at the West African and Central Pacific region to be inconsistent with the defined theory of the declination angle influence on the spread F longitudinal distribution (Tsunoda et al, 2015). Likewise, Huang, (2017) reported an anti-correlation between the vertical plasma drift and the small amplitude irregularity during the moderate solar activity period.…”

Section: Introductionmentioning

confidence: 97%

“…CC BY 4.0 License. conjugate E regions that are coupled to the F region (Abdu et al, 1992;Tsunoda et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Spread F occurrence features at different longitudinal regions during low and moderate solar activity

Afolayan

Mandeep

Abdullah

et al. 2019

Preprint

View full text Add to dashboard Cite

Abstract. A comparative study of the equatorial spread F occurrence was conducted at different longitudes during 2009 or 2010 and 2011 or 2013 which represents the low (LSA) and moderate (MSA) solar activity periods respectively. The ionogram data were recorded at low latitude stations including Jicamarca (JIC; 75.76° W, 8.17° S), Peru; Fortaleza (FZA; 38.52° W, 3.73° S), Brazil; Ilorin (ILR; 7.55° E, 9.93° N), Nigeria; Chumphon (CPN; 88.46° E, 11° N), Thailand and Kwajalein (KWA; 167.73° E, 8.72° N), Marshal Island. The range type spread F (RSF) occurrence was manually recorded at an hour interval between 18:00–06:00 LT and a monthly average of the RSF occurrence was estimated for each of the seasons. The observed features of the RSF occurrence and its longitudinal distribution at different seasons include the difference in the onset time, duration and peak of occurrence. The significant observations include the asymmetric RSF occurrence distribution during the equinoctial season at most of the longitudes, while during the solstice seasons there are cases of discrepancy in the RSF occurrence with respect to the sunset terminator-magnetic field alignment. The inconsistent pattern of the RSF occurrence percentage and the post-sunset rise of the F layer in relation to the sunset time lag were analyzed. While the possible role of the seed perturbation effect was discussed with respect to some of the peculiar features observed in the longitudinal/seasonal distribution of the spread F occurrence percentage.

show abstract

Effects of tidal forcing, conductivity gradient, and active seeding on the climatology of equatorial spread F over Kwajalein

Cited by 27 publications

References 83 publications

Upwelling: a unit of disturbance in equatorial spread F

Upwelling: a unit of disturbance in equatorial spread F

Effects of the postsunset vertical plasma drift on the generation of equatorial spread F

Spread F occurrence features at different longitudinal regions during low and moderate solar activity

Contact Info

Product

Resources

About