Seasonal and solar activity dependence of storm time TEC variations for a low latitude station Palehua

Abstract

The enhancement and depletions of the total electron content (TEC) on storm days from the quiet day values are analysed for different seasons and solar activity conditions at Palehua, a low latitude station, during the period 1980–1991.Considering the dependence of enhancement in storm time TEC for positive storms with solar radio flux F10.7, a positive correlation is observed in winter and equinox. For negative storms, the correlation of depletion in storm time TEC with solar radio flux F10.7 is positive in equinox, but no such dependency is observed in summer. The intensity of storm ( A p ) is found to be negatively correlated with enhancement in storm time TEC, in equinox, for positive storms. But no such dependency is shown in winter. For negative storms, the depletion in storm time TEC shows no dependency with A p in equinox, but shows positive correlation in summer. Considering the dependence of enhancement of TEC on D st max, a positive correlation is observed in winter and equinox for positive storms. For negative storms, the correlation between depletion in storm time TEC and D st max is found to be positive for summer and equinox. A similar correlation study is carried out for time delay (τ) of occurrence of maximum enhancement and depletion of TEC. The maximum and minimum percentage probability range of ΔTEC and τ are also analysed by considering the data seasonally.