Longitudinal comparisons of the brightness peak intensity (top panel) and radial position (bottom panel) of the volume emissivity maximum between radio bands and epochs. Profiles are derived from cartography of equatorial brightness distribution using either a Single Value Decomposition approach (lines) or a three-dimensional Fourier technique (star symbols) (from Figs. 5 and A.1). Error bars were calculated for the L-band observations and represent one standard deviation. They are placed as they would follow the mean longitudinal profiles, which are not plotted for clarity reasons.