An improved empirical formulation of an ionosphere bottomside electron density profile thickness parameter

An improved empirical formulation for the characterization of the “base point” of the bottomside ionospheric electron density profile is proposed. The “base point” in an ionospheric layer is defined by the electron density profile height where the gradient dN/dh reaches a maximum. The difference between the height of the maximum electron density and the height of the “base point” is proportional to the ionospheric F2 layer thickness parameter B2. The previous empirical formula links the maximum value of dN/dh to foF2 and M(3000)F2 scaled from the ionograms. The new formulation adds a dependence on the solar zenith angle. The use of the new equation improves substantially the calculation of the B2 thickness parameter used in the NeQuick model.