The temperature of the<i>F</i>region deduced from electron number-density profiles

Abstract

Electron number-density-height profiles of the ionosphere were deduced from ionograms taken at Lindau/Harz during noon intervals and years of high and low solar activity. The curvature of these profiles close to the F2 peak was determined by a parabolic approximation and expressed by the half-thickness Ym of this parabola. These Ym values proved to be proportional to the respective neutral gas temperature at the peak as deduced from satellite drag measurements. The upper and lower limits were ±10%, respectively. This result differed from recent theoretical studies and suggested more detailed studies in this field. The seasonal peak height variation of the F2 layer was shown to mirror the exospheric temperature anomaly. It was concluded that both anomalies might have the same origin, namely, dynamical effects in the ionosphere and exosphere. In completion, data on the heating of the ionosphere during mean geomagnetic disturbances deduced by a lunar tidal analysis of the same real height data were added. A rate of 5.8°K per unit of Ap was found.