Model of traveling ionospheric disturbances

Abstract

A multiscale semi-empirical model of traveling ionospheric disturbances (TIDs) is developed. The model is based on the following assumptions: (1) TIDs are generated by acoustic-gravity waves (AGWs) and propagate as pressure waves; (2) time intervals between adjacent extrema of atmospheric pressure oscillations in a disturbance source are constant; (3) the pressure extrema propagate from the source up to~14 000 km at a constant horizontal velocity; (4) the velocity of each extremum is determined only by its number in a TID train. The model was validated using literature data on disturbances generated by about 20 surface and highaltitude nuclear explosions, two volcano explosions, one earthquake and by energetic proton precipitation events in the magnetospheric cusp of the northern hemisphere. Model tests using literature data show that the spatial and temporal TID periods may be predicted with an accuracy of 12%. Adequacy of the model was also confirmed by our observations collected using transionospheric sounding. The following TID parameters: amplitudes, horizontal spatial periods, and a TID front inclination angle in a vertical plane are increasing as the distance between an AGW and the excitation source is increasing. Diurnal and seasonal variability of the TID occurrence, defined as ratio of TID events to the total number of observations for the corresponding period, is not observed. However, the TID occurrence was growing from~50% in 1987 to~98% in 2010. The results of other studies asserting that the TID occurrence does not depend on the number of sunspots and magnetic activity are confirmed. The TID occurrence has doubled over the period from 1987 to 2010 indicating increasing solar activity which is not associated with sunspot numbers. The dynamics of spatial horizontal periods was studied in a range of 150-35 000 km.Key words. semi-empirical model -multiscale traveling ionospheric disturbances -horizontal velocity of extremum -nuclear explosion -volcano explosive eruption -energetic proton precipitation -magnetospheric cusp -transionospheric soundingdisturbance occurrence -sunspot number -magnetic activity

LBCS: The LOFAR Long-Baseline Calibrator Survey

“…This complex picture reflects the complicated nature of the ionosphere, which features short time-and spatial-scale disturbances together with larger travelling ionospheric disturbances (e.g. Intema et al 2009;Fedorenko et al 2013). We defer a full discussion of the ionospheric constraints provided by LBCS to a future work, after completion of the full survey.…”

Direct Observations of Traveling Ionospheric Disturbances as Focusers of Solar Radiation: Spectral Caustics

“…MSTIDs are characterized by spatial and temporal periods of 100-600 km and 0.25-1 h, respectively (Hunsucker 1982). They can propagate as the guided wave mode in a mirror-like layer at heights 250-300 km above the ground (Fedorenko et al 2013). Because of its nature the density perturbation consists of alternating structural cells with high and low magnitudes of electron concentration.…”

Traveling Ionosphere Disturbance Signatures on Ground‐Based Observations of the O(1D) Nightglow Inferred From 1‐D Modeling

“…Candido et al () showed that the maximal occurrence rate of MSTID happens during solar minimum. Nonetheless, Fedorenko et al () claim that TID occurrence does not depend on the sunspot number, while Klausner et al () show that TIDs have larger amplitudes during high solar activity. Thus, there are still opportunities for deeper investigation of the occurrence rate of TID around the globe to confirm these reports.…”