Time series of the TiO images (first row), Hα–4 Å raster images (second row), and vertical velocity maps of the Ti II (third row) and Hα (fourth row). The contours on the Hα–4 Å raster images and the vertical velocity maps indicate the granules obtained from the TiO images. A purple cross symbol in the first TiO image (t = 13.6 min) marks the selected position that was further analyzed and is shown in Figs. 8 and 9.