Evolution (left to right) of the Ca ii 8542 Å intensity profile (solid black line) displayed for the most conspicuous scans (1 and 18 to 20) in four selected areas (1–4, top to bottom). The four areas are also marked in all other figures. Overplotted in solid red is the best fit from the NICOLE inversions in the spectral range −0.8 ≤ Δλ ≤ 1.2 Å. The same pixel was chosen for each scan. The time corresponds to the midpoint of each scan. For reference, the dotted profile shows the average quiet-Sun profile.