Empirical regional models for the short-term forecast of M3000F2 during not quiet geomagnetic conditions over Europe

摘要

Twelve empirical local models have been developed for the long-term predictionof the ionospheric characteristic , and then used as starting point for thedevelopment of a short-term forecasting empirical regional model of under not quiet geomagnetic conditions. Under the assumption that themonthly median measurements of are linearly correlated to the solaractivity, a set of regression coefficients were calculated over 12 monthsand 24 h for each of 12 ionospheric observatories located in theEuropean area, and then used for the long-term prediction of at eachstation under consideration.Based on the 12 long-term prediction empirical local models of , an empiricalregional model for the prediction of the monthly median field of over Europe(indicated as ) was developed.Thanks to the models, which are able to provide short-term forecasts of thecritical frequency of the F2 layer (F2) up to three hours in advance,it was possible to considerer the Brudley–Dudeney algorithm as a function ofF2 to correct and thus obtain an empirical regional modelfor the short-term forecasting of (indicated as ) up to three hours inadvance under not quiet geomagnetic conditions.From the long-term predictions of provided by the IRI model, an empiricalregional model for the forecast of the monthly median field of over Europe(indicated as ) was derived. predictions were modified with the Bradley–Dudeney correction factor, andanother empirical regional model for the short-term forecasting of (indicated as ) up to three hours ahead under not quiet geomagneticconditions was obtained.The main results achieved comparing the performance of , , , and are (1) in the case of moderate geomagnetic activity, the Bradley–Dudeneycorrection factor does not improve significantly the predictions; (2) underdisturbed geomagnetic conditions, the Bradley–Dudeney formula improves thepredictions of in the entire European area; (3) in the case of very disturbedgeomagnetic conditions, the Bradley–Dudeney algorithm is very effective inimproving the performance of ; (4) under moderate geomagnetic conditions,the long-term prediction maps of generated by can be considered asshort-term forecasting maps providing very satisfactory results becausequiet geomagnetic conditions are not so diverse from moderate geomagneticconditions; (5) the forecasting maps originated by , ,and show some regionswhere the forecasts are not satisfactory, but also wide sectors where the forecasts quite faithfully match the observations, and therefore, , and could be exploited to produce short-term forecasting maps of overEurope up to 3 h in advance.