function dy=scm_fun(t,y)
dy = zeros(2,1);    % a column vector
% time step = one year
% constant definition
tau_atm=2.82;      % time constant for atmosphere in years
tau_ocean=100.3;   % time constant for ocean in years
alfa=3.23;         % coupled strength
fa=0.367;          % climate sensitivity for atmosphere [K/W/m^2]
fo=0.0689;         % climate sensitivity for ocean [K/W/m^2]
RF=2.0;
dy(1)=1/tau_atm*(-y(1)+fa*RF+alfa*y(2));
dy(2)=1/tau_ocean*(-y(2)+fo*RF);
