[Spectral modeling of marine suspended particulate matter: comparison between ADA and Mie computations]

The present paper aimed at exploring the feasibility of modeling optical properties of marine suspended particulate matter (SPM) with anomalous diffraction approximation (ADA) method, which had advantage of computation speed over the classic Mie theory. Based on the marine SPM characteristics of refractive index and particle size, attenuation efficiency Q(c) absorption efficiency Q(a) and scattering efficiency Q(b) of SPM were computed by ADA and Mie to analyze their relative error delta(c), delta(a), delta(b) and the variations. The variations of delta(c), delta(a), delta(b) with the particle size, real and imaginary part of refractive index were different and complex. The minimum particle size R(min), with which ADA can be used to give computation results with enough accuracy (relative difference less than 5%), was determined and shown to be influenced by the refractive index and wavelength Classic Mie method, rather than ADA method, was recommended for the spectral modeling of ocean suspended particulate matter.