Yadav, Sneha and Upadhayaya, A. K. and Das, Rupesh M. (2012) Daytime additional F layer stratification over low-midlatitude station of the Indian sector under geomagnetic disturbed conditions. Journal of Geophysical Research Atmospheres, 117. A0632-A0645. ISSN 0148-0227

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In this paper, the observations of additional F layer stratification are presented in a region which is situated at the outer edge of equatorial ionization anomaly (EIA) zone. The digital ionosonde data observed over Delhi (28.6 degrees N, 77.2 degrees E, dip 42.44 degrees N) during March-April, 2001 has been used to carry out the present work. The observational period was geomagnetically disturbed and represents the high solar activity phase of 23rd solar cycle. The additional transient cusp is frequently observed in the considered months before the noon hours; however, in this paper only five prominent cases are presented. From the analysis of ionograms, it is observed that the transient additional cusp is formed between the pre-existing F-1 and F-2 layer; hence, named as the cusp of F1.5. Study reveals that the Traveling Atmospheric Disturbances (TADs) along with the vertical expansion of F layer provides the necessary condition for the existence of this transient feature. The intensification of F-1 layer along with increased altitude immediately after the disappearance of additional stratification remains one of the fascinating features of the present results. The present investigation demonstrates that the daytime F-1 and F-2 region over low-midlatitude station is strongly modulated by the passage of TIDs, originating at high latitudes or by atmospheric disturbances of local origin during the high solar activity period. The concurrent presence of TADs and the associated disturbance composition appears to be plausible reason behind the present observations.

Item Type: Article
Additional Information: Copyright for this article belongs to M/s American Geophysical Union.
Subjects: Astronomy & Astrophysics
Depositing User: Users 27 not found.
Date Deposited: 07 Feb 2020 10:20
Last Modified: 07 Feb 2020 10:20
URI: http://npl.csircentral.net/id/eprint/3655

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