Size Distribution of Raindrops Generated by their Breakup and Coalescence

Abstract

Some computations of the evolution of raindrop-size distributions under the operation of the processes of drop breakup and coalescence are presented. It is found that the size distribution approaches a stationary state. The stationary size distributions for different rainfall rates are roughly parallel to each other when logf(r) is plotted against r, f(r) being the concentration density of drops of radius r. A comparison with observations shows that the computed distributions are flatter than the observed ones. It is suggested that other processes besides the breakup and coalescence of raindrops shape their distribution with size.