Forecasting the local ionospheric f_oF_2 parameter 1 hour ahead during disturbed geomagnetic conditions

摘要

Using the support vector machine (SVM), an empirical local ionospheric forecasting model over Lanzhou (ELIFMOL) has been developed to predict the critical frequency of the F_2 layer (f_oF_2) during disturbed geomagnetic conditions. This study focuses on the reliable prediction of f_oF_2 during geomagnetic storms, which is important for practical applications as well as for further understanding of the storm dynamics. In this paper, we investigate whether f_oF_2 during disturbed geomagnetic conditions at a single station can be well predicted one hour ahead by using some inputs to an SVM network, such as the latest f_oF_2 observations, hourly quiet time f_oF_2 (f_oF_(2QT)), time, and the hourly time-weighted accumulation series derived from the geomagnetic index (ap(τ)). The input observation data cover the period of January 1958 to December 2000 at Lanzhou (36.1°N, 104.0°E) in China. The f_oF_2 forecasted by the ELIFMOL are compared with the monthly median values and with those by the STORM_(MEDIAN) model, the persistence model, and the STORM_(foF2QT) model during geomagnetic storms occurring from 2001 to 2006. As for the data sets used in this paper, the results show that the performance of ELIFMOL is better than that of the latter models.