Peak strength in the limit of a broad PDF with as function of the critical column density below which the carriers of the peak are assumed to be destroyed. The intrinsic peak strength as given by Fitzpatrick (1999) is shown as dashed line. The corresponding peak strength of a turbulent screen model with no additional destruction is shown as dotted line. The dashed-dotted and the three dashed-dotted curves are the approximations in the regime and given in Eqs. (A.21) and (A.23).