Scattering functions of tropospheric aerosols: the effects of nonspherical particles.

Scattering functions, i.e., the scattered intensity as a function of angle, are modeled for tropospheric aerosol types with respect to the effect of the nonspherical shape of the particles. Scattering functions of nonspherical particles compared with those of equivalent spheres show differences increasing with particle size. Thus, for aerosol types with a relatively low amount of large particles, such as continental and urban aerosols, the effect due to uncertainty about particle shape can be ignored, compared to effects due to uncertain particle size and refractive index. In desert aerosol the nonspherical particles systematically increase side scatter with a maximum around a scattering angle of 120 degrees , while around 160 degrees the difference between scattering functions of spheres and nonspheres is small. With increasing wavelength the influence of nonspherical particles decreases.