Numerical relaxation timescale as function of column mass determined numerically (solid line) compared to the timescale determined from eigenvalues of the rate matrix in the initial statistical equilibrium states (dot-dashed). The thick lines represent the averages over all time steps between t = 600 s and t = 2350 s, whereas the thin lines are for a particular time step at t = 1620 s. Minimum and maximum values for both dynamic and eigenvalue timescales during the considered time window are shown as grey dotted lines. For reference, the height scale at t = 1620 s is given on top.