Climatology of Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) Observed with GPS Networks in the North African Region

Abstract

We present for the first time the climatology of medium-scale traveling ionospheric disturbances (MSTIDs) by using Global Positioning System (GPS) receiver networks on geomagnetically quiet days (Kp ≤ 3) over the North African region during 2008-2016. The ionospheric Total Electron Content (TEC) were estimated from the dual-frequency GPS measurements, and the TEC perturbations (dTEC) data were derived from the estimated TEC data. We focused on the TEC perturbations (dTEC) associated with medium-scale traveling ionospheric disturbances (MSTIDs) and statistically analyzed the MSTIDs characteristics, occurrence rate, diurnal and seasonal behavior as well as the interannual dependence. The oscillating wave-like pattern of MSTIDs showed a local and seasonal dependence of nighttime and daytime. The results showed that MSTIDs propagation direction is predominantly towards the South (equatorward), MSTIDs event period is (12 ≤ period ≤ 53 mins), and dominant amplitude (0.08 ≤ amp ≤ ~1.5 TECU), with a propagation velocity higher at daytime than nighttime. The amplitudes of the MSTIDs increase with solar activity. The study reveals that the spatio-temporal variation of MSTIDs depends on local time and solar activity. The study also shows that the disturbance occurrence time is dominant within the hours of (1200–1600 LT), and (1000–1400 LT) in December solstice at daytime for stations located in the Northwest (NW) and Northeast (NE) part of the African region, respectively. While at the nighttime, the MSTIDs exhibits variability in disturbance occurrence time around (NW: 2100–0200 LT) and (NE: 1900–0200 LT) in June solstice, but get extended to March equinox during solar maximum (2014). The mean phase velocity in daytime MSTIDs is higher than the nighttime in every season, except during June solstice. The study revealed that atmospheric gravity waves (AGWs) control the daytime MSTIDs occurrence for a selected day.

Statistics of Traveling Ionospheric Disturbances at High Latitudes Using a Rapid‐Run Ionosonde

“…Just recently a more efficient way of MSTID detection were also shown using simultaneous Nordic Meteor Radar Cluster and EISCAT VHF measurements in the high latitude region (Günzkofer et al., 2023). However, most TID statistical studies at low, mid and high latitudes were made by GNSS methods of trans‐ionospheric sounding due to the easily available data of total electron content (TEC) (Afraimovich et al., 1999; Ding et al., 2011; Oluwadare et al., 2022). Our study focuses on the diurnal and seasonal MSTIDs characteristics inferred from the foF2 ionosonde data, which were earlier used mostly to observe background ionospheric ionization.…”