Apparent widths of the Sun at several levels in EW (top) and NS (bottom) directions for three radio frequencies (150 MHz at left, 236 MHz at middle, 432 MHz at right), between 2004 and 2011. The curves, labeled with the brightness temperature T_b (kK), give yearly-averaged values. The vertical bars give the rms dispersions for each year. They are slightly shifted relative to each other in order not to overlap.