Wave behaviors at the LBs 1 and 2. The top two rows show time–space diagrams along slits 2 and 3 (averaged over a width of 20 pixels) in Figure 1(a), where the left panels show the Hα intensity and the right panels show the Doppler velocity. The middle row displays variations of the Doppler velocity (black) and Hα intensity (blue) averaged over a width of 30 pixels between two black lines shown in the top panels. The bottom panels show cross-wavelet transforms (similar those in Figure 1) for the time series of signals between Doppler velocity and Hα intensity as shown in the middle panels.