Moment-1 maps (top), smoothed moment-1 maps obtained using the kernel defined in Equation (41) (middle), and filtered moment-1 maps (bottom) for the ﹩{\dot{M}}_{{\rm{in}}}=1{0}^{-7}\,{M}_{\odot }\,{{\rm{yr}}}^{-1}﹩ at t = 2, 4, and 12 kyr. The spiral arms identified from the filtered moment-0 maps and the Doppler-flip locations are overplotted in the bottom panels as solid gray curves and a dashed magenta circle, respectively. The smoothed moment-1 maps primarily highlight the large-scale disk warp induced by streamer accretion, while the filtered moment-1 maps reveal velocity perturbations associated with streamer-induced disk substructures.