Power spectra of longitudinal velocity, i.e., velocity parallel to the field (black) and vertical velocity (red) at the full resolution of simulations. Power spectra of vertical velocity for degraded simulation data with an effective resolution of 100 km (blue) and 200 km (green). Dashed curve displays a power-law fit to the black curve in the frequency range 6–25 mHz in each panel. Different panels correspond to different heights as mentioned in each panel. Here, “a” and “b” are the amplitude and the exponent for the power law.