An empirical ionospheric storm-time correction model

An empirical model for F-region peak ionospheric storm-time changes has been developed based on understanding from theoretical modeling of geomagnetic storms. The model is designed to scale climatology, or monthly-medians, based on the strength of a storm, as a function of geomagnetic latitude, season, and local time. The model is driven by an index derived from the previous thirty hours of auroral or geomagnetic activity, suitably weighted by a filter. The model is particularly effective in capturing the ionospheric storm negative phase in summer mid latitudes, where it reduces the root-mean-square error by more than a factor of two. The winter mid-latitude F region typically experiences a positive phase during a storm accompanied by a high degree of variability. The model does less well in these circumstances but still makes a significant reduction in the variance. The ionospheric storm-time model can be used to scale monthly median values or a quiet time model such as the International Reference Ionosphere. (C) 1999 COSPAR. Published by Elsevier Science Ltd.