Indices of equatorial electrojet and counter-electrojet in the Indian region: evolution of the indices and their authenticity

Bhargava, B. N. ; Arora, B. R. ; Sastri, N. S. (1983) Indices of equatorial electrojet and counter-electrojet in the Indian region: evolution of the indices and their authenticity Proceedings of the Indian Academy of Sciences - Earth and Planetary Sciences, 92 (1). pp. 45-55. ISSN 0253-4126

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Official URL: http://www.ias.ac.in/j_archive/epsci/92/1/45-55/vi...

Related URL: http://dx.doi.org/10.1007/BF02936463

Abstract

Indices of the equatorial electrojet and counter-electrojet in the Indian region have been evolved based on certain reasonable assumptions, by a criterion depending on the difference in the horizontal field strength between a station under the electrojet axis (Trivandrum) and a station outside the jet influence (Alibag). The indices enable one to characterize each day of the year by an appropriate index. Distribution, in the months, seasons and over the years, of the electrojet and counter-electrojet frequencies at Trivandrum during a 20-year period, 1959-78, is examined. The salient features of the distributions are: (i) Strong electrojets (range 50 nT) and the afternoon counter-electrojets occur, on an average, on about 50% of the days in the year; (ii) For the counter-electrojet, the monthly frequencies show an annual variation with a summer maximum, and for the strong electrojet, a semi-annual variation with maxima in the equinoxes; (iii) A secondary maximum is noted in January in the occurrence frequency of both counter-electrojet and strong electrojet events; (iv) Intense electrojets occur with greater frequency in September.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Electrojet; Counter-electrojet; Indices; Frequency Distribution; Solar Cycle Modulation; Lunar Modulation
ID Code:959
Deposited On:25 Sep 2010 10:06
Last Modified:14 May 2011 10:16

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