MoMo empirical model results for the Northern (left) and Southern (middle) hemispheres. The colours correspond to the different seasons (i.e., Ls); the solid, dashed and doted lines represent high, moderate and low solar activity level respectively. Also represented are the radio occultation data (Peter et al., 2014) for different solar activity levels: high (triangle), moderate (square) and low (circle). On the right is the scatter plot showing the MoMo prediction model versus the vTEC from the Mars Express radio occultation data for the two hemispheres.