Figure 4

Yearly positive breaks. Positive breaks detected in vTEC derived from GPS satellite 15 and GEONET receiver 3009 (top) and GPS satellite 23 and IGS receiver IQQE (bottom) plotted as a function of the day of year (DOY). The total number of breaks (Ntot) found by AIC method (Δt = 60 min, ThA = 3 TECU/h−1 and ThR = 75%) is written on the right side of the plot.