Improved analytical representation of electron temperature in the IRI

In the last decade extensive measurements from incoherent scatter stations and from several satellite missions have considerably improved our knowledge of long- and short-term variations in the ionospheric electron temperature. Comparisons with IRI have revealed some shortcomings of this earlier model. It is obvious that in different altitude regions one has to concentrate the modelling efforts on different parameters. Here a model representation is proposed that will facilitate approaches (for the different altitude regions) in one analytic form.