Mean rise time (top) and decay time (bottom) as a function of frequency for all the analysed type III bursts as found from the HWHM, t_r and t_d, respectively. The top and bottom blue dashed lines show the spread of the data, found from the standard deviation. The red dashed line show the fits t_r = (1.5± 0.1) f^{−0.77±0.14} and t_d = (2.2 ± 0.2) f^{−0.89±0.15} for frequency (per 30 MHz). For the decay time, the green and orange dashed lines show the fits from Evans et al. (1973) and Alvarez & Haddock (1973a), respectively, assuming a HWHM of t_d = τ_d log(2), from the derived exponential profiles τ_d.