APPLICATION OF RANDOMLY ORIENTED SPHEROIDS FORRETRIEVAL OF DUST PARTICLE PARAMETERS FROM MULTIWAVELENGTH LIDAR MEASUREMENTS

Desert dust is responsible for a significant part of the total atmospheric aerosol loading, thus development of methods for the remote study of dust particle microphysical properties is demanded. Multiwavelength (MW) Raman lidars have demonstrated their potential to profile particle parameters, however up to the present, the physical models used in retrieval algorithms for processing MW lidar data have been based on Mie theory. This approach is applicable for modeling light scattering by spherical particles only and does not adequately reproduce the scattering by generally non-spherical desert dust particles. Here we present an algorithm using a model of randomly oriented spheroids for inversion of multi-wavelength lidar data. Following the positive experience of retrieval developments within AERONET, we model aerosols as a mixture of two aerosol components: one composed only by spherical and second composed by non-spherical particles. The algorithm was tested with experimental data from a Saharan dust outbreak episode, measured with the BASIL multi-wavelength Raman lidar in August 2007.