Empirical model of ionospheric storm effects on the F2 layer peak height associated with changes of peak electron density

Abstract

An empirical model of storm‐time behavior of the ionospheric peak heighthmF2 associated with changes of peak electron density NmF2is inferred from the topside true‐height profiles provided by ISIS 1, ISIS 2, IK‐19, and Cosmos‐1809 satellites for the period of 1969–1987. The topside‐derived quiet‐time models of the ionospheric peak heighthqF2 and peak electron density NqF2are used as a frame of reference. To harmonize the model with storm and substorm effects induced by large‐scale traveling ionospheric disturbances (LSTIDs), constraints are applied to the topside data, excluding their changes deviating above LSTID extreme limits. The degree of disturbance is estimated by the ionospheric weatherW index; then, the least squares fitting is applied to the median of log(hm/hq) versus log(Nm/Nq). Anticorrelation between instant changes of hmF2 and NmF2has a particular seasonal‐magnetic latitude structure varying with solar activity that is used for the buildup of the analytical model. The model allows the deduction of the instantaneoushmF2 associated with the assessment or forecast of the respective NmF2. The model is validated with the data of five ground‐based ionosondes during severe space weather storms at times of high solar activity (2000) and low solar activity (2006), and results agree reasonably well with the peak parameters derived from an ionogram. The model is incorporated into the coupled International Reference Ionosphere‐Plasmasphere (IRI‐Plas) code, used in the assimilative mode as the three‐dimensional (3‐D) interpolator of the GPS‐derived total electron content, TECgps.