Retrieval of the aerosol size distribution from spectroradiometer measurements at a coastal site in the Mediterranean Sea

Values of aerosol optical depth, tau(a lambda), have been obtained from spectral irradiance measurements registered at Valencia (Spain) between July 1993 and June 1995. Aerosol size distribution functions were calculated by considering these tau(a lambda) values and by using the inversion method proposed by King. The results show that such functions are bimodal, with a primary mode that is not apparent and a clearly defined secondary mode in the range 0.5-0.8 mu m. Generally, the shape of the distribution function does not depend on the complex refractive index m assigned to the aerosols, although an increase in the imaginary part of in produces a decrease in the function's minimum.