function sigma_rr=RR_comb(T)
nt=length(T);
g=inline('(1/(sqrt(2*pi)*.1274))*exp(-0.5*((x-353.25)/.1274).^2)');

gg=0;
for k=1:nt
    NN2=0.;
    gg=0.;
    for nline=6:30
       [a1,a2,a3,err]=diff_backscatter(354.7,T(k),nline,-1,'nitrogen');
       gg=gg+g(a3);
       NN2=NN2+g(a3)*a1;
    end
    NN2=NN2/gg;
    NO2=0.;
    gg=0.;
    for oline=6:30
        [a1,a2,a3,err]=diff_backscatter(354.7,T(k),oline,-1,'oxygen');
        gg=gg+g(a3);
        NO2=NO2+(0.21/.78)*g(a3)*a1;
    end
    NO2=NO2/gg;
    sigma_rr(k)=NN2+NO2;
end


% figure
% plot(X,(Q_comb))
% hold on
% %plot(X,1/Q_NN2,'r')
% %plot(X,1/Q_NO2,'g')
% legend
