Morphological characteristics of ionospheric E layer over El Cerrillo station, Mexico during magnetically quiet conditions

Abstract

We have used foE data obtained during magnetically quiet conditions to describe the behavior of the E region at El Cerrillo, Mexico. This region is in photochemical equilibrium and its shape fits the parabolic geometry of Chapman's theory. If the isothermal assumption is relaxed and constant gradients of scale heights dH/dh=0.2 are assumed, the exponent N of a linear regression matches closely Chapman's predictions. Maximum values of foE occur slightly after local noon, and depend on the level of solar activity. During daytime foE rises 7 to 10 times, with the highest rate of increase occurring during Low Solar Activity periods. There is a clear tendency for foE to increase with solar activity.