%  function [Ft] = calc_Ft(Te,Ta,Ts,EPSA)
%
    function [Ft] = calc_Ft(Te,Ta,Ts,EPSA)
    
%Read parameters
  TwoBox_Param

%TOA flux
  Ftdown = SIGMA*Te^4;
  Ftup = SIGMA*(EPSA*Ta^4+(1-EPSA)*Ts^4);
  Ft = Ftdown-Ftup; %>0 downward