COSPAR colloquium on low-latitude ionospheric physics

Abstract. Rapid radio soundings were made over Ahmedabad, a low latitude station during the period 16–20 November 1998 to study the sporadic-E layer associated with the Leonid shower activity using the KEL Aerospace digital ionosonde. Hourly ionograms for the period 11 November to 24 November were also examined during the years from 1994 to 1998. A distinct increase in sporadic-E layer occurrence is noticed on 17, 18 and 19 November from 1996 to 1998. The diurnal variations of f0Es and fbEs also show significantly enhanced values for the morning hours of 18 and 19 November 1998. The ionograms clearly show strong sporadic-E reflections at times of peak shower activity with multiple traces in the altitude range of 100–140 km in few ionograms. Sporadic-E layers with multiple structures in altitude are also seen in some of the ionograms (quarter hourly) at Thumba, situated near the magnetic equator. Few of ionograms recorded at Kodaikanal, another equatorial station, also show sporadic- E reflections in spite of the transmitter power being significantly lower. These new results highlighting the effect of intense meteor showers in the equatorial and low latitude E-region are presented.Key words. Ionosphere (equatorial ionosphere) – Radio science (ionospheric physics)

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Low latitude ionospheric physics

Journal of Atmospheric and Terrestrial Physics ◽

10.1016/0021-9169(95)90050-0 ◽

1995 ◽

Vol 57 (13) ◽

pp. 1676

Author(s):

M.A. Abdu

Keyword(s):

Low Latitude ◽

Ionospheric Physics

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

International Journal of Geophysics ◽

10.1155/2012/938057 ◽

2012 ◽

Vol 2012 ◽

pp. 1-22 ◽

Cited By ~ 12

Author(s):

M. V. Klimenko ◽

B. Zhao ◽

A. T. Karpachev ◽

V. V. Klimenko

Keyword(s):

Electric Field ◽

Physical Mechanism ◽

Equatorial Ionosphere ◽

Layer Formation ◽

Low Latitude ◽

Meridional Component ◽

Ionospheric Physics ◽

Additional Layer ◽

Plasma Diffusion ◽

History Of

A large number of researches have been devoted to the formation of additional layers in theFregion of the equatorial ionosphere, first of which has been published in 1940s. Originally the occurrence of such layer was named “stratification of equatorialF2layer.” The additional layer was later named as theF3layer. The theoretical researches have shown that theF3layer 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 theF3layer formation is clearly formulated for the morning-noon period, although theF3layer 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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Progress report on 21-cm observations at low latitude between longitudes (l 11) 0° and 66°

Symposium - International Astronomical Union ◽

10.1017/s0074180900100907 ◽

1967 ◽

Vol 31 ◽

pp. 177-179

Author(s):

W. W. Shane

Keyword(s):

Preliminary Report ◽

Progress Report ◽

Galactic Centre ◽

Low Latitude ◽

The Third ◽

Introductory Lecture ◽

Centre Region

In the course of several 21-cm observing programmes being carried out by the Leiden Observatory with the 25-meter telescope at Dwingeloo, a fairly complete, though inhomogeneous, survey of the regionl11= 0° to 66° at low galactic latitudes is becoming available. The essential data on this survey are presented in Table 1. Oort (1967) has given a preliminary report on the first and third investigations. The third is discussed briefly by Kerr in his introductory lecture on the galactic centre region (Paper 42). Burton (1966) has published provisional results of the fifth investigation, and I have discussed the sixth in Paper 19. All of the observations listed in the table have been completed, but we plan to extend investigation 3 to a much finer grid of positions.

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