A numerical model is used to investigate the dependence at 351 nm of desert-aerosol extinction and backscatter coefficients on particle imaginary refractive index (m i ). Three ranges (-0.005 ≤ m i ≤ -0.001, -0.01 ≤ m i ≤ -0.001, and -0.02 ≤ m i ≤ -0.001) are considered, showing that backscatter coefficients are reduced as |m i | increases, whereas extinction coefficients are weakly dependent on m i . Numerical results are compared with extinction and backscatter coefficients retrieved by elastic Raman lidar measurements performed during Saharan dust storms over the Mediterranean Sea. The comparison indicates that a range of -0.01 to -0.001 can be representative of Saharan dust aerosols and that the nonsphericity of mineral particles must be considered.
© 2004 Optical Society of America
Maria Rita Perrone, Francesca Barnaba, Ferdinando De Tomasi, Gian Paolo Gobbi, and Anna Maria Tafuro, "Imaginary Refractive-Index Effects on Desert-Aerosol Extinction Versus Backscatter Relationships at 351 nm: Numerical Computations and Comparison with Raman Lidar Measurements," Appl. Opt. 43, 5531-5541 (2004)