Global median empirical model of Total Electron Content (GTEC) is developed driven by re-calibrated sunspot numbers, SSN2, for the quiet geomagnetic conditions (ap < 15 nT). The based on Spherical Harmonic Analysis (SHA) Ionospheric Maps GIM-TEC provided JPL from 1996 to 2019. SHA coefficients are calculated low solar activity (SSN2 ? 20) and high ? 100) linear interpolation applied between the...