Analysis of Optical Properties of Saharan Dust Derived From Dual-Wavelength Aerosol Retrievals From CALIPSO Observations

Since its first collection of data in June of 2006, the Cloud and Aerosol LIdar with Orthogonal Polarization (CALIOP) lidar instrument aboard the CALIPSO satellite has observed numerous Saharan dust events over West Africa and the Atlantic, predominantly from late May through early September. Due to CALIOP´s sensitivity to polarization at 532 nm, the depolarization arising from scattering from the nonspherical dust particles serves as an independent means of discrimination between dust and other aerosol species. In addition to being an important and frequently observed class of aerosol, the Saharan dust provides an excellent basis for the evaluation of elastic-scatter lidar retrieval techniques. The Constrained Ratio Aerosol Model-fit (CRAM) method is one such technique, which applies aerosol modeling constraints in order to limit the ambiguity inherent in aerosol retrievals from elastic-scatter lidar. This letter, in addition to investigating the overall scattering properties of Saharan dust, highlights various retrieval approaches useful in determining the scattering properties of aerosols, as observed by the CALIOP instrument. Herein, we attempt to arrive at an improvement in the dust aerosol model used within CRAM.