An Improved Empirical Model for Electron Temperature in the F2-Region

42-47A short review of all the available model techniques for the estimation of F2-region ionospheric electron temperature is first presented and then a new model is proposed which, in addition to the electron density control, also includes the solar activity control, not contained in any of the earlier models. This is achieved by obtaining coefficients relating electron temperature with, electron density and solar activity from incoherent scatter radar measurements at Arecibo (lat., 18.3°N; long., 67°W) for thee, period Aug. 1966 to May 1977, which covers solar cycle 20 and a rising part of solar cycle 21. The model is valid for any level of solar activity with the 81-day averaged 10.7-cm solar radio flux varying from 70 to 180 units. Comparison of the model Te values with actual measurements from incoherent scatter radars and rocket and satellite probes, for various levels of solar activity and at different locations, shows reasonable agreement The International Reference Ionosphere (IRI) model however shows large departures from the actual measurements