Abstract: This paper observed the interhemispheric conjugate
auroral activity occurred on 21 September 2009. The GPS derived
ionospheric total electron content (TEC) during a weak substorm
interval recorded at interhemispheric conjugate points at Husafell in
Iceland and Syowa in Antarctica is investigated to look at their
signatures on the auroral features. Selection of all-sky camera (ASC)
images and keogram at Tjörnes and Syowa during the interval
00:47:54 – 00:50:14 UT on 21 September 2009 found that the auroral
activity had exerted their influence on the GPS TEC as a
consequence of varying interplanetary magnetic field (IMF) By
polarity.