Temporal evolution of the differences with respect to the pure photosphere state of 2000 (see also Fig. 1). Data were averaged for each observing epoch. In seasons with only a few observing epochs (FEROS 2001, 2002, and HARPS 2003) residual pulsational profile distortions are clearly seen in the line cores. Mg ii 4481 shows circumstellar absorption in HARPS 2003, UVES 2006, and FEROS 2006, similar to the CQE seen in Fig. 2. Rest wavelengths of spectral lines are indicated with a dashed line, excess wing signature depression with arrows.