Effects of Height of F2-Layer on Critical Frequency at Low Latitudes Using Data and a Numeric Model
Ionosphere investigation leads to the knowledge of its composition in particles. The density in
particles determines the capacity of this region to reflect radio waves in the atmosphere at different
heights. Some variables such as season and solar cycle phase also influence the ionosphere
behavior. Radio waves frequencies pass through the ionosphere layer without reflection above a
critical value determining the critical frequency. The density in particles in this region is variable from
daytime to nighttime and during the seasons of the year. The solar cycle phases also influence the
composition in particles of ionosphere region.
Many models are developed to give a good approach of ionosphere region. Some of them are
mathematical simulations. A good model must match with data results of parameters.
This study determines, in first time, the critical frequency of radio waves in the F2 layer (foF2) of the
ionosphere by use of data during the minimum and the maximum of solar cycle 22, at different
seasons with the height of F2-layer (hmF2). It presents the hourly behavior of foF2 according to hmF2
values. In second time, Thermosphere-Ionosphere-Electrodynamics General Circulation Model
(TIEGCM) is used to give an approach for ionosphere description. TIEGCM has been developed at
National Center for Atmospheric Research (Boulder, Denver, Colorado State, USA). This model is
used to carry out the Critical frequency of F2-layer and the Height of F2-layer in ionosphere. Local
time links these parameters during quiet time periods for solar cycle 22. The study takes place at
Ouagadougou station, in West Africa, near equator. The study also proposes a new approach to
evaluate the annual values of these parameters. It gives good correlation with the results found by
running other models such as International Reference Ionosphere (IRI) model in the same conditions.
Author (s) Details
Centre National de la Recherche Scientifique et Technologique (CNRST), Institut de Recherche en Sciences Appliquées et Technologies (IRSAT), 03 BP 7047 Ouagadougou 03, Burkina Faso.
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