Mean deviation of each events’ rotation angle, ϕ_rot, from the rotation angle corresponding to the ISD inflow vector, ϕ_ISD, for the union (blue circles), the Krüger (orange triangles), the Strub (green squares), and the intersect (violet diamonds) subsets, averaged over Δt = 4 months beginning on 1 January 1992. Horizontal error bars denote the width of the time bin, and vertical error bars were calculated with Eq. (B.10), taking into account wall impacts (cf. Fig. B.1). Grey-shaded areas and letters at the top edge are as in Fig. 5. (After Janisch 2021, Fig. 5.17.)