Ionospheric total electron content observed during the 24 October 1995 solar eclipse

During the solar eclipse of October 24, 1995, the effect of an eclipse on the total electron content (TEC) of the ionosphere can be investigated by using measurement of the Global Positioning System (GPS). The TEC derived from five GPS ground-based receivers have been used to observe ionospheric variations over the geomagnetic equatorial, equatorial anomaly, and mid-latitude regions. The deviations in the TECs on the eclipse day from those on reference days show that during the eclipse days the ionosphere experienced some changes. Four features of the TEC deviations, pre-ascension (PA), major depression (MD), sunset ascension (SA), and secondary depression (SD) have been observed. Possible mechanisms explaining in the four features are investigated and discussed.