Frequency dependence of diffractive timescales t_DISS (top left), refractive timescales t_RISS (top right), refractive modulation index m_RISS (bottom left), and decorrelation bandwidth BWm_RISS (bottom right). Data taken from Bhat et al. (1999) at 327 MHz, Gupta et al. (1994) at 408 MHz, Stinebring et al. (1996) at 610 MHz, Wang et al. (2005) at 1.5 GHz, and this paper at 4.8 GHz. The solid line presents the fit to observed data.