Optical properties of Saharan dust aerosol and contribution from the coarse mode as measured during the Fennec 2011 aircraft campaign - Ryder,CL; Highwood,EJ; Rosenberg,PD; Trembath,J; Brooke,JK; Bart,M; Dean,A; Crosier,J; Dorsey,J; Brindley,H; Banks,J; Marsham,JH; et al. (ATMOSPHERIC CHEMISTRY AND PHYSICS, 2013)