function [P,ext,SSA]=MieRayleigh(Pa,Pm,ext_a,ext_m,ssa,ext_O3,ext_O2);
%combine MIE and Rayleigh optical properties
ext=ext_a+ext_m+ext_O3+ext_O2;
SSA=(1*ext_m+ssa*ext_a+0*ext_O3+0*ext_O2)./ext;
P=(Pm.*1.*ext_m+Pa*ssa.*ext_a)./(1*ext_m+ssa.*ext_a);


