ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Springer Verlag Göttingen, Germany 10.1007/s00585-997-0314-9 Self-consistent modelling of the daytime electron density profile in the ionospheric F region Mikhailov A. 1 2 Schlegel K. 1 Max-Planck-Institut für Aeronomie, Postfach 20, D-37189 Katlenburg-Lindau, Germany <i>Permanent address:</i> Institute for Applied Geophysics, 129128 Rostokinskaya 9, Moscow, Russia 31 03 1997 15 3 314 326 Copyright: © 1997 A. Mikhailov 1997 © European Geosciences Union 1997 This article is available from https://angeo.copernicus.org/articles/15/314/1997/angeo-15-314-1997.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/15/314/1997/angeo-15-314-1997.pdf

A theoretical self-consistent method for the description of daytime <i>N<sub>e</sub>(h)</i> profiles in the ionospheric F region measured by EISCAT is proposed. It is based on the use of a theoretical F-region model and measured electron density, <i>N<sub>e</sub>(h)</i>, electron, <i>T<sub>e</sub>(h)</i>, and ion temperature, <i>T<sub>i</sub>(h)</i>, and field-aligned plasma drift <i>V<sub>l</sub>(h)</i> profiles. The method describes the observed <i>N<sub>e</sub>(h)</i> profile with high accuracy for quiet and disturbed conditions. Two versions of the method are considered: in the first the exospheric temperature <i>T<sub>ex</sub></i> is derived from a procedure minimizing [log(<i>N<sub>e</sub>(h)</i><sub>obs</sub> / <i>N<sub>e</sub>(h)</i><sub>cal</sub>]<sup>2</sup>, in the second <i>T<sub>ex</sub></i> is deduced from the ion energy conservation in the F region. The method allows us to infer from the incoherent-scatter observations: concentrations of atomic oxygen, [O], molecular oxygen, [O<sub>2</sub>], molecular nitrogen, [N<sub>2</sub>] the vertical plasma drift, <i>W</i>, the exospheric temperature. <i>T<sub>ex</sub></i>, and the shape parameter <i>S</i> in the neutral temperature profile. The ratio ([O<sup>+</sup>]/<i>N<sub>e</sub></i>) calculated by the theoretical model is used to correct <i>T<sub>e</sub>(h), T<sub>i</sub>(h)</i> and N<sub>e</sub>(h)</i> profiles routinely measured with EISCAT which are known to depend strongly on the actual applied ion-composition model. Such a correction is especially important for geomagnetically disturbed periods when the F region is strongly enriched with molecular ions. We conclude that four of the six thermospheric parameters, namely [O], [N<sub>2</sub>], <i>W</i> and <i>T<sub>ex</sub></i> can be confidently inferred from the EISCAT observations, while the other two derived parameters, [O<sub>2</sub>] ans <i>S</i> are less reliable. The method can be used for the analysis of long-term (seasonal, solar cycle) as well as for day-to-day variations of the thermospheric parameters and the F-region ion composition using daytime incoherent-scatter observations.