New formulae based on the Sech-squared, Exponential and Chapman layers are introduced for a TEC-based electron density reconstruction technique using ionosonde and upper ion transition level data. These analytical ionospheric models are implemented and tested as reconstruction tools with the help of satellite in-situ measurements of the ion and electron densities. Particular attention is drawn to the calculation quality of the scale height in the upper ionosphere, from hmF2 up to the O+-H+ transition height.
Investigated is the relationship between the level of geomagnetic activity and the GPS TEC relative deviations from the monthly medians. Detailed information on this dependence is of crucial importance for developing a new synthetic index which, by quantifying the local response of TEC to geomagnetic activity, will be able to improve the quality of autocorrelation forecast procedures.</o:p>
Authors:S. M. Stankov, I. S. Kutiev, N. Jakowski, and A. Wehrenpfennig
The GPS-derived TEC has proved to be a robust characteristic representing well the state of the Earth's ionosphere-plasmasphere system during both quiet and disturbed geomagnetic conditions. Successfully forecasting the TEC value can prove invaluable when trying to improve the communications, navigation, and surveying practices. Presented is a new forecasting method based on auto-correlation analysis and consisting of two major parts - first, extrapolation of the TEC monthly medians using Fourier series approximation, and second, geomagnetically-correlated forecast of the TEC relative deviations of from its median value. Preliminary tests show a good agreement between measured and predicted median values. Presented are also important investigations related to the short-term forecast.
Authors:S. M. Stankov, R. Warnant, and J. C. Jodogne
Presented is a new operational model for real-time reconstruction of the vertical electron density distribution from concurrent GPS-based total electron content and ionosonde measurements. The model is developed on the basis of a novel approach for deducing the topside ion scale heights assuming Exponential, Epstein, or Chapman type of vertical density distribution. The required input data are submitted on-line to an operational centre where processing is carried out immediately and the electron density profile is derived. The method is suitable for use at middle and high latitude locations where ionosonde measurements are available. Several tests have been carried out and preliminary results have been presented and discussed.