Equatorial spread F and sporadic E-layer connections during the Brazilian Conjugate Point Equatorial Experiment (COPEX)

Abstract. Directional ionogram and F-region drift observations were conducted at seven digisonde stations in South America during the COPEX campaign from October to December 2002. Five stations in Brazil, one in Argentina, and one in Peru, monitored the ionosphere across the continent to study the onset and development of F-region density depletions that cause equatorial spread F (ESF). New ionosonde techniques quantitatively describe the prereversal uplifting of the F layer at the magnetic equator and the eastward motion of the depletions over the stations. Three of the Brazilian stations were located along a field line with a 350-km apex over the equator to investigate the relation of the occurrence of ESF and the presence of sporadic E-layers at the two E-region intersections of the field line. No simple correlation was found.

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Effects of sporadic E-layer characteristics on spread-F generation in the nighttime midlatitude ionosphere: A climatological study

Journal of Atmospheric and Solar-Terrestrial Physics ◽

10.1016/j.jastp.2018.02.002 ◽

2018 ◽

Vol 169 ◽

pp. 130-137

Author(s):

C.C. Lee ◽

W.S. Chen

Keyword(s):

Midlatitude Ionosphere ◽

Spread F ◽

Sporadic E Layer ◽

Sporadic E

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Observations of GPS ionospheric scintillations over Wuhan during geomagnetic storms

Annales Geophysicae ◽

10.5194/angeo-24-1581-2006 ◽

2006 ◽

Vol 24 (6) ◽

pp. 1581-1590 ◽

Cited By ~ 14

Author(s):

G. Li ◽

B. Ning ◽

W. Wan ◽

B. Zhao

Keyword(s):

Geomagnetic Storms ◽

Equatorial Ionosphere ◽

The Other ◽

Small Scale ◽

Plasma Drift ◽

Equatorial Ionization Anomaly ◽

Spread F ◽

Ionospheric Scintillations ◽

Sporadic E Layer ◽

Sporadic E

Abstract. During the two geomagnetic storms which occurred on 1 October 2002 and 22 January 2004, the strong ionospheric scintillations of the GPS L1 band were observed at Wuhan station (30.6° N, 114.4° E, 45.8° Dip), which is situated near the northern crest of the equatorial ionosphere anomaly. We found that the intense scintillations were associated with the main phases of the storms and were co-located with the enhancement of the equatorial ionization anomaly (EIA); the co-existence of large- and small-scale irregularities at post-midnight was also found. The results may be relevant regarding the influence of the equatorial ionospheric eastward electric field during geomagnetic storms. On the other hand, GPS L1 band scintillations were not observed during the other two similar storms on 16 July 2003 and 20 November 2003. One of the reasons is probably that the sporadic E layer observed at the storms inhibited the generation of spread F by changing the Pedersen conductivity and suppressing the upward plasma drift.

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Prediction of Equatorial Spread F Based on Assimilation of Daytime GPS Data

10.21236/ada628801 ◽

2003 ◽

Author(s):

Michael C. Kelley

Keyword(s):

Gps Data ◽

Equatorial Spread F ◽

Spread F

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Equatorial Spread-F and Magnetic Activity

Nature ◽

10.1038/1811724a0 ◽

1958 ◽

Vol 181 (4625) ◽

pp. 1724-1725 ◽

Cited By ~ 22

Author(s):

A. J. LYON ◽

N. J. SKINNER ◽

R. W. WRIGHT

Keyword(s):

Magnetic Activity ◽

Equatorial Spread F ◽

Spread F

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Observations of Equatorial Spread F

Geophysical Monograph Series - Ionosphere Dynamics and Applications ◽

10.1002/9781119815617.ch11 ◽

2021 ◽

pp. 201-280

Author(s):

Roland T. Tsunoda

Keyword(s):

Equatorial Spread F ◽

Spread F

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Seasonal dependence of the "forecast parameter" based on the EIA characteristics for the prediction of Equatorial Spread F (ESF)

Annales Geophysicae ◽

10.5194/angeo-26-1751-2008 ◽

2008 ◽

Vol 26 (7) ◽

pp. 1751-1757 ◽

Cited By ~ 10

Author(s):

S. V. Thampi ◽

S. Ravindran ◽

T. K. Pant ◽

C. V. Devasia ◽

R. Sridharan

Keyword(s):

Seasonal Variability ◽

Seasonal Pattern ◽

Onset Time ◽

Critical Value ◽

Latitudinal Gradients ◽

Electron Content ◽

Total Electron ◽

Equatorial Spread F ◽

Spread F ◽

Definite Role

Abstract. In an earlier study, Thampi et al. (2006) have shown that the strength and asymmetry of Equatorial Ionization Anomaly (EIA), obtained well ahead of the onset time of Equatorial Spread F (ESF) have a definite role on the subsequent ESF activity, and a new "forecast parameter" has been identified for the prediction of ESF. This paper presents the observations of EIA strength and asymmetry from the Indian longitudes during the period from August 2005–March 2007. These observations are made using the line of sight Total Electron Content (TEC) measured by a ground-based beacon receiver located at Trivandrum (8.5° N, 77° E, 0.5° N dip lat) in India. It is seen that the seasonal variability of EIA strength and asymmetry are manifested in the latitudinal gradients obtained using the relative TEC measurements. As a consequence, the "forecast parameter" also displays a definite seasonal pattern. The seasonal variability of the EIA strength and asymmetry, and the "forecast parameter" are discussed in the present paper and a critical value for has been identified for each month/season. The likely "skill factor" of the new parameter is assessed using the data for a total of 122 days, and it is seen that when the estimated value of the "forecast parameter" exceeds the critical value, the ESF is seen to occur on more than 95% of cases.

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