Hysteresis loops for photometric cycles. Upper panel: Estimated photometric cycles along with the line-depth ratios of VI and Fe I. The ratios are determined from the spectra. Consequently, the ratios also show which part of a photometric cycle is covered by the data. Lower panels: Hysteresis loops relate the phase shift between the variations of velocity and temperature. To demonstrate the evolution of material in atmospheric layers more clearly, the values were binned in two-week intervals. Most cycles lack significant parts of the loops due to an insufficient number of measurements (especially in the first half of the data) and observation gaps; therefore, in many cases full loops are not observed. The black arrows indicate the direction of a loop, which almost always is as we would expect, that is, counterclockwise. Continued in Fig. A.2.