Topside sounder model of scale height and transition height characteristics of the ionosphere

The topside scale height (Ts) and transition height (Th) models, previously developed by the authors, provided Ts and Th for any set of input parameters: month, local time, geomagnetic latitude, solar flux F-107, and Kp. It was found that the scale height and transition 0(+)-H+ height, extracted from each individual measured Ne profile, highly correlate, with a correlation coefficient exceeding 0.8 at mid-latitudes. The ratio Rt = Ts/Th obtained from the individual profiles is modelled as a function of the same input parameters. Three subsets of data, for Ts, Th, and Rt, were organized to obtain the respective model coefficients. The three models: Ts, Th, and Rt are now incorporated in a single model TSM (topside sounder model). It is found that Ts and Th have a dispersion of about 40% around the respective average, while the model reduces the dispersion (model error) to 27%. The most remarkable fact is that the dispersion of Rt is only 25% and model error is reduced to 18%. This fact promotes Rt as an reliable parameter in the topside modeling. The main variations of the model quantities versus geomagnetic latitude and local time are shown for different conditions. It is shown that the model values capture well the data variations. TSM output parameters are used to formulate a concept of a new profiler, named topside ionosphere and plasmasphere profiler (TIPP), as a tool for obtaining the vertical Ne distribution in the upper ionosphere and plasmasphere when NmF2 and hmF2 are specified. The concept consider either the sech-squared, alpha-Chapman, or exponential shape of the topside F layer, which have to be tested against the measured profiles for selecting most reliable. (C) 2006 COSPAR. Published by Elsevier Ltd. All rights reserved.