Position-velocity diagrams investigating the ¹²CO 1–0/H i cloud ensembles #1–#3 identified in Figs. 3, 4 (white arrows, see also Sect. 3.3) at various latitudes. The distributions of the H i (color) and ¹²CO 1–0 (contours) are plotted against the Galactic longitude, kept as the x axis, as in Fig. 2. The H i and ¹²CO 1–0 lines have been summed in a) over b = −1.4° to b = −0.7° to highlight negative-latitude cloud ensembles and in b) over the b = −0.5° to b = 0.3° latitude range of the W43 molecular complex. The contours of a) go from 150 to 1200 K with a step of 150 K. Those of b) run from 300 to 1200 K, with a step of 300 K. The white boxes represent the longitude extent and velocity range of the W43 molecular complex (continuous lines) and its H i envelope (dashed lines). The negative-latitude cloud ensemble #1 can easily be identified in a) and the other two cloud ensembles can be seen in b).