Abstract
Abstract. An ionospheric forecasting empirical local model over Rome (IFELMOR) has been developed to predict the state of the critical frequency of the F2 layer (foF2) during geomagnetic storms and disturbed ionospheric conditions. Hourly measurements of foF2 obtained at the Rome observatory, hourly quiet-time values of foF2 (foF2QT), and the hourly time-weighted accumulation series derived from the geomagnetic planetary index ap (ap(τ)), were considered during the period January 1976–December 2003. Under the assumption that the ionospheric disturbance index log(foF2/foF2QT) is correlated to the integrated geomagnetic index ap(τ), statistically significant regression coefficients are obtained for different months and for different ranges of ap(τ) and used as input to calculate the short-term ionospheric forecasting of foF2. The empirical storm-time ionospheric correction model (STORM) was used to make comparisons with the IFELMOR model. A few comparisons between STORM's performance, IFELMOR's performance, the median measurements and the foF2QT values, were made for significant geomagnetic storm events (ap>150) occurring from 2000 to 2003. The results provided by IFELMOR are satisfactory, in particular, for periods characterized by high geomagnetic activity and very disturbed ionospheric conditions.
Highlights
A large number of global (Jones and Gallet, 1962; Comite Consultatif International des Radio Communications (CCIR), 1991; International Telecommunication Union (ITU), 1997) and regional models (Bradley, 1999; Hanbaba, 1999) have been developed over the years in order to predict the monthly medians of the key ionospheric characteristic of the F2 layer, such as its critical frequency, frequency of the F2 layer (foF2), and the obliquity factor for a distance of 3000 km, M(3000)F2
Under the assumption that the ionospheric disturbance index log(foF2/foF2QT ) is correlated to the integrated geomagnetic index ap(τ ), statistically significant regression coefficients are obtained for different months and for different ranges of ap(τ ) and used as input to calculate the short-term ionospheric forecasting of foF2
The results provided by ionospheric forecasting empirical local model over Rome (IFELMOR) are satisfactory, in particular, for periods characterized by high geomagnetic activity and very disturbed ionospheric conditions
Summary
1999) have been developed over the years in order to predict the monthly medians of the key ionospheric characteristic of the F2 layer, such as its critical frequency, foF2, and the obliquity factor for a distance of 3000 km, M(3000)F2. There is a need to develop now-casting models (AraujoPradere et al, 2002; Zolesi et al, 2004; Pietrella and Perrone, 2005) and short-term forecasting models (Cander et al, 1998; Muhtarov and Kutiev, 1999; Oyeyemi et al, 2005) for the prediction of foF2 for a few hours ahead This would provide HF operators with real-time or quasi-real-time assistance in choosing the optimal frequencies for radio links, even in the case of a strongly disturbed ionosphere. The ionospheric forecasting empirical local model, to predict the state of the critical frequency of the F2 layer, foF2, over Rome (IFELMOR), during geomagnetic storms and disturbed ionospheric conditions, was developed with the assumption that there is an empirical relationship between IDI and geomagnetic activity. A few comparisons between STORM’s performance, IFELMOR’s performance, the median measurements and the foF2QT values, are shown for significant geomagnetic storm events (ap>150) and for disturbed ionospheric conditions occurring from 2000 to 2003
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