Approximation of the size distribution of marine particles by a sum of log-normal functions

A simple algorithm is presented that decomposes the size distribution of marine particles into a sum of log-normal components of the Oth order. The algorithm was applied to 412 particle-size distributions in a particle-diameter range of similar to 0.5-200 mu m measured by different researchers in various water bodies. A size distribution from this population may have from 1 to 6 log-normal components. The variability of the number of components reflects the variability in the shape of the size distribution and variations in the size range in which the data are available. The full-width-at-half-maximum of a component is approximately proportional to the peak diameter of the component. The maximum value of a component is approximately proportional to the inverse of the square of the peak diameter. Two standard components of the marine particle-size distribution were identified. The peak diameter (D-peak), width parameter (sigma), and maximum value (FDmax), of the first component are, respectively, 0.66 mu m, 0.673, and 1.34 x 10(4) mu m(-1) cm(-3). These parameters for the second component are 10.5 mu m, 0.366, and 3.3 mu m(-1) cm(-3).