Simulated temperature and the response of the Ca II 8542 Å line to temperature changes. Top panel: temperature as a function of height (vertical axis) and time (horizontal axis) at a randomly chosen spatial position. Red lines indicate the height of the peak of the response function of intensity to temperature (thickest line) and delimit the range of heights where the normalized response function is above 0.7 (medium-thick lines), and above 0.5 (thinner lines). Bottom panel: vertical stratification of the temperature at some selected time steps. The color of the line indicates the corresponding time step, as given by the dashed vertical lines in the top panel.