Preliminary Results of Ionosonde Measurements at Waltair (17.7 degree N) during the Total Solar Eclipse of October 24, 1995

Abstract

The digital ionosonde system at Waltair was operated continuously from 23rd to 27th October 1995. The maximum percentage of obscuration (81%) of the solar disc occurred at 08.44 hrs IST as seen from Waltair on the eclipse day, i.e., 24th October 1995. A study on the temporal variation of h'F, f, F1, fo F2 and dh'F/dt on the eclipse day are presented. The h'F showed an oscillatory behaviour during the course of the eclipse. Thereafter, the h'F decreased upto 12 Hrs IST merging with the control day trend of variation henceforth. In comparison with the temporal variation of fo F2 on the control day, fo F2 dropped by about 15% around 09.14 Hrs IST (i.e., about 30 minutes after maximum obscuration of the solar disc) on the eclipse day. On the other hand, fo F1 decreased by as much as 50% on the eclipse day with no time lag between the time of maximum obscuration and the time of maximum decline of fo F1.