Features of the<i>F</i><sub>3</sub>layer in the low-latitude ionosphere at sunset

Wan, Weixing; Reinisch, B. W.; Yue, Xinan; Le, Huijun; Liu, Jing; Xiong, Bo

doi:10.1029/2010ja016111

Cited by 30 publications

(63 citation statements)

References 48 publications

(67 reference statements)

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“…The statistic of the F3 layer occurrence at Chumphon (10.7 • N, 99. [66]. Thus these results suggest that the difference in seasonal dependence of the occurrence probability between Indian and Brazil may not be mainly caused by the difference of the geographic longitude but that of the magnetic latitude.…”

Section: Inconsistency Of the Observation On Thementioning

confidence: 62%

“…Zhao et al [66] have also presented the statistical result at Fortaleza using the data during 2007-2010 which shows much lower occurrence in winter different from the result of Balan et al [35] based on the data during 1995. It should be noted that the magnetic latitude of Fortaleza changes from −4.4 • to the present −7.0…”

Section: Inconsistency Of the Observation On Thementioning

confidence: 96%

“…Similarly, according to the ground-based data F3 layer is observed rarely at the equator than at low latitudes ±(7∼8 • ) [37,39,41,65]. Recent studies show that the F3 layer near the magnetic equator behaves in a different way than that in the magnetic low-latitude region [41,43,66]. The F3 layer moves rapidly upward near the magnetic equator, while it stays almost at a certain altitude in the magnetic low-latitude region.…”

Section: Latitudinal Dependence Of the F3 Layermentioning

confidence: 99%

“…According to Balan et al [35], the F3 layer winter occurrence though high lasts for very short period during the morning local time when E × B drift is very effective. The sunset F3 layer has a strong seasonal dependence occurring mainly during the summer time [66]. The contradiction in the statistical result may also partly suffer from the fact that the judgment of the stratification of F2 layer is very subjective and no uniform standard has been applied to judge the difference between the fully developed and unfinished stratification.…”

Section: Inconsistency Of the Observation On Thementioning

confidence: 99%

“…Balan et al [35] suggested that although the driving force undergoes a large and sudden upward strengthening during the evening hours, formation of another layer at lower altitudes is unlikely to occur when the F2 layer drifts upward, because of the absence of the production of ionization. However, Depuev and Pulinets [51], Karpachev et al [52], and Zhao et al [66] described the case of the F3 layer occurrence at night (00:00-04:00 LT) and at post sunset time (18:00-21:00 LT at Figure 15). Klimenko et al [46] and M. V. Klimenko and V. V. Klimenko [48] demonstrated that the F3 layer is formed as a result of the nonuniformity in height vertical E×B plasma drifts at the geomagnetic equator.…”

Section: Mechanism Of the Quiet-time F3mentioning

confidence: 99%

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Stratification of the Low-Latitude and Near-EquatorialF2Layer, Topside Ionization Ledge, andF3Layer: What We Know about This? A Review

Клименко¹,

Karpachev²,

Клименко³

2012

International Journal of Geophysics

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A large number of researches have been devoted to the formation of additional layers in the F region of the equatorial ionosphere, first of which has been published in 1940s. Originally the occurrence of such layer was named "stratification of equatorial F2 layer." The additional layer was later named as the F3 layer. The theoretical researches have shown that the F3 layer is formed by zonal component of electric field with assistance of meridional component of thermospheric wind and field-aligned plasma diffusion. The physical mechanism of the F3 layer formation is clearly formulated for the morning-noon period, although the F3 layer is also observed at other hours. This paper presents a brief review into the history of the additional layer researches, describes the current progress of these researches, and identifies the most important problems in this field of the ionospheric physics.

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Section: Inconsistency Of the Observation On Thementioning

confidence: 62%

Section: Inconsistency Of the Observation On Thementioning

confidence: 96%

Section: Latitudinal Dependence Of the F3 Layermentioning

confidence: 99%

Section: Inconsistency Of the Observation On Thementioning

confidence: 99%

Section: Mechanism Of the Quiet-time F3mentioning

confidence: 99%

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Stratification of the Low-Latitude and Near-EquatorialF2Layer, Topside Ionization Ledge, andF3Layer: What We Know about This? A Review

Клименко¹,

Karpachev²,

Клименко³

2012

International Journal of Geophysics

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Peculiar features of ionospheric F₃ layer during prolonged solar minimum (2007–2009)

Nayak¹,

Yadav²,

Kakad³

et al. 2014

JGR Space Physics

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We present the seasonal and local time occurrence of ionospheric F3 layer over Tirunelveli (geographic longitude 77.8°E, geographic latitude 8.7°N, dip 0.7°) during extremely low and prolonged solar activity period (2007–2009). Canadian Advanced Digital Ionosonde observations from this station are used in the present study. We find that the occurrence of F3 layer is nearly 3 times higher during 2009 (∼ 48%) as compared to that during 2007 (∼16%). The increase of this order just within the low solar activity period is unusual. In earlier studies similar increase in F3 occurrence has been reported when solar activity changes from high (F10.7=182) to low (F10.7=72). The other important feature is the presence of postnoon F3 layers which are observed dominantly during summer solstice of 2009. Such occurrence of postnoon F3 layers was nearly absent during summer solstice of the previous solar minimum (1996) over nearby dip equatorial station Trivandrum. We take equatorial electrojet (EEJ) as a proxy for eastward electric field. It is noticed that the EEJ strength and the maximum rate of change of EEJ are higher for F3 days as compared to those on non‐F3 days. We find that the peak occurrence of prenoon F3 layer closely coincides with the time of maximum rate of change of EEJ. It is in general accordance with the theory proposed by Balan et al. (1998) that suggests the formation of F3 through vertically upward E × B drift in presence of equatorward neutral wind. The present study reveals that the rate of change of eastward electric field (dE/dt) as well plays an important role in the formation of F3 layer.

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An empirical model of the occurrence of an additional layer in the ionosphere from the occultation technique: Preliminary results

et al. 2014

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About 8 year electron density profile (EDP) data from the COSMIC/FORMOSAT-3 satellites radio occultation technique were used to investigate the additional stratification of the F2 (the so-called F3 layer) layer over the equatorial and low-latitude ionosphere on a global scale for both the bottomside and topside ionosphere. The F3 layer was recognized through the altitude differential profile featured by two maxima existing from the selected EDP profile. There were~37,000 (bottomside) and 25,000 (topside) cases of F3 layer selected out of~1.27 million occultation events at equatorial and low-latitude areas during the period of April 2006 to August 2014. The statistical results for the bottomside ionosphere resemble that reported in Zhao et al. (2011a), while in the topside the highest occurrence of F3 layer shows a 3-4 h delay depending on the altitude range of the stratification. The magnetic latitude distribution shows different dependence with a tendency to form a single crest toward high altitude. Also, the seasonal variation is weaker in the topside ionosphere compared to the bottomside one, especially in the high altitude. Then we build up an empirical model of the F3 layer occurrence using the bottomside statistics based on empirical orthogonal function (EOF) decomposition as it gets the inherent characters inside the data set and converges quickly. The model well grasps the main features of the F3 occurrence, e.g., the F3 occurrence's sensitivity on the magnetic latitude. Further, in order to accommodate the ground observation a corrected factor was introduced. As F3 layer is an important phenomenon in the low-latitude ionosphere, we have made an attempt to describe its feature with a consecutive function although future work needs to be done for an overall expression of this structure.

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Features of theF₃layer in the low-latitude ionosphere at sunset

Cited by 30 publications

References 48 publications

Stratification of the Low-Latitude and Near-EquatorialF2Layer, Topside Ionization Ledge, andF3Layer: What We Know about This? A Review

Stratification of the Low-Latitude and Near-EquatorialF2Layer, Topside Ionization Ledge, andF3Layer: What We Know about This? A Review

Peculiar features of ionospheric F₃ layer during prolonged solar minimum (2007–2009)

An empirical model of the occurrence of an additional layer in the ionosphere from the occultation technique: Preliminary results

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Features of theF3layer in the low-latitude ionosphere at sunset

Cited by 30 publications

References 48 publications

Stratification of the Low-Latitude and Near-EquatorialF2Layer, Topside Ionization Ledge, andF3Layer: What We Know about This? A Review

Stratification of the Low-Latitude and Near-EquatorialF2Layer, Topside Ionization Ledge, andF3Layer: What We Know about This? A Review

Peculiar features of ionospheric F3 layer during prolonged solar minimum (2007–2009)

An empirical model of the occurrence of an additional layer in the ionosphere from the occultation technique: Preliminary results

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Product

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Features of theF₃layer in the low-latitude ionosphere at sunset

Peculiar features of ionospheric F₃ layer during prolonged solar minimum (2007–2009)