ANGEO

Annales Geophysicae

ANGEO

1432-0576

Copernicus GmbH

Göttingen, Germany

10.5194/angeo-19-59-2001

Sporadic-E associated with the Leonid meteor shower event of November 1998 over low and equatorial latitudes

Chandra

¹ Sharma

¹ Devasia

C. V.

² Subbarao

K. S. V.

² Sridharan

² Sastri

J. H.

³ Rao

J. V. S. V.

Physical Research Laboratory, Ahmedabad, India 380 009

Space Physics Laboratory, VSSC, Trivandrum, India 695 022

Indian Institute of Astrophysics, Bangalore, India 560 034

30 11 1999

19 1 59 69

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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)