Charles M. Rush, Margo PoKempner, D. N. Anderson, and Frank G. Stewart

Abstract: In this report, the results of a study to improve the global maps of monthly median values of the F2 region critical frequency, foF2, using values determined from a theoretical model, are presented. The object of the study was to obtain values of the mid– latitude F–region critical frequency which could be used to improve the prediction of ionospheric parameters in regions of the earth inaccessible to ground–based measurements. This was accomplished by including, into the theoretical calculations, realistic physical processes along with a realistic geomagnetic field model. Parameters were adjusted so that agreement was achieved between calculated and observed foF2 values as a function of local time at different stations and then these same input parameters (i.e., neutral wind field, neutral atmospheric model, electrodynamic drift) were assumed valid at all regions of interest where the major difference is the geomagnetic field–line configuration. Coefficients that yield global representations of foF2 were then determined using the theoretically derived foF2 values, and the predicted critical frequencies were compared with observed values to estimate the degree of improvement.

Keywords: foF2; ionospheric mapping; neutral winds; time-dependent continuity equation

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

For questions or information on this or any other NTIA scientific publication, contact the ITS Publications Office at ITSinfo@ntia.gov or 303-497-3572.

Back to Search Results