Signature of the 29 March 2006 eclipse on the ionosphere over an equatorial station

摘要

This study documents some results of the effect of the 29 March 2006 eclipse on the ionosphere over Ilorin, Nigeria (longitude 4.57°E, latitude 8.53°N, dip 4.1°S), an equatorial station in the West African region. The maximum obscuration of the eclipse at this station was 99 percent and it occurred before midday. True height electron density profile analysis below the F2 peak was employed in the study. The effect on the E and F1 layers was a drastic decrease in electron density, with maximum decrease percentages of 60 and 68 for the E and F1 layers, respectively. A decrease in foF2 began at about 1 hour 20 min after those in the lower layers had started. Variation of electron density with height showed that the decrease in the electron density occurred through out the E and F1 heights at about the same time while that of the F2 region began at lower heights and extended progressively toward the peak of electron density height of the layer. The recovery in the E and F1 layers has already reached an advanced stage before the effect of the eclipse got to the maximum in the F2 region. A major departure of hmF2 from the normal variation was observed and discussed.