Publisher: Bachudo Science Co. Ltd

Local Time Dependence of Ionospheric Current Correlations In Low Latitudes

C. Agodi Onwumechili, P. O. Ezema
KEYWORDS: ionospheric currents, correlation coefficients, local time dependence.


The study of the correlation of the daily ranges AH at all local time hours, at 7 stations close to the same longitude, has given more information on the correlation of ionospheric current intensities and their changes than is obtainable from daily ranges only. At night· time, the correlation coefficients of all pairs of stations are positive, very high and independent of the distance between the two correlating stations. They are attributed to magnetospheric sources. The correlation coefficients of two stations in the equatorial electrojet (EEJ) zone or two stations in the worldwide part of the Solar Quiet daily variation Sq (WSq) zone outside the influence of the EEJ are positive, very high and remain fairly steady for all hours of the day. In contrast, the correlation coefficient of a station in EEJ zone with a station in WSq zone is very high and steady at night-time but in daytime, it decreases drastically to low and ,mostly insignificant values. All the correlation coefficients between Jaipur and stations equatorward of it are unduly low. These results have been discussed and explained in terms of the following current systems: the EEJ current system occasionally modulated by the counter equatorial electrojet (CEJ) current system, and the WSq current system occasionally modulated by the single vortex current (SVC) system. The correlations involving Jaipur are unduly low because the AH from the SVC responsible for the low values is effective only in the region of about 12°-S5 ° latitude.

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