Figure 7 . Sensitivity analysis where initial conditions use final rainfall patterns from Case 3 (a) and Case 4 (b), and examples from the eastern flank of the Peruvian Andes (c) and eastern-central Himalaya (d). Panel layouts are the same as in Figure 3b. Triangular fields in demarcated in black dashes in (a) and (b) bound rainfall gradients with the same pattern as the initial condition (i.e., bottom-heavy or top-heavy), but cause complex transient responses similar to those expected for reversals in polarity of the rainfall pattern as the rainfall becomes relatively bottom- or top-heavy – see section 5.1 for further discussion. Panels (c & d) show examples of climate change scenarios from model simulations reported in supplementary tables by Mutz et al. (2018), for a hypothetical transverse river with parameters in Table 1. Initial condition is set in the Pliocene (PLIO), and representative evolution of the orographic rainfall pattern through to the Last Glacial Maximum (LGM) is plotted, illustrating that climate changes that are predicted to trigger complex responses are likely not uncommon.