Behavior of the scale height at the F2 layer peak derived from Digisonde measurements at two European stations

A new technique is presented to estimate the electron density topside profile from information derived from ground-based ionograms. The electron density above the F2 peak is approximated by an α-Chapman function with constant scale height (H _m ). The scale height is derived from the shape of the bottomside profile near the F2 peak. Digisonde data obtained at two European stations: Ebro (40.4°N, 0.3°E) and El Arenosillo (37.1°N; 353.2°E) for different times of day, seasons, and periods of the solar cycle to study the variations of H _m . The results of the analysis are in good agreement with those reported by other authors. A table of values is presented for typical hours of the day and different seasons and solar activity conditions. This study, once extended to a larger database, will support modeling H _m as a function of time, season, latitude, solar activity and magnetic activity, and contribute to the formulation of the topside electron density in the IRI model.