Jokulhlaup Hydrograph & Phase-Plane (2D R-Channel Model)

This is the 2D companion to the 3D subglacial-lake-outburst simulator. It keeps the exact same physical model — a Röthlisberger channel's cross-sectional area evolving under competing viscous-dissipation melt-opening and Glen's-law ice-creep closure, coupled to a lake water balance — but represents it through genuinely 2D-native instruments instead of a rendered ice cutaway: a scrolling discharge hydrograph (the trace a real stream gauge would record) and a channel-area/effective-pressure phase-plane plot that turns the model's unstable threshold and runaway feedback into visible geometry — something a 3D tube animation cannot show directly. Adjust ice thickness, slope and recharge, trigger an outburst, and watch both the hydrograph and the phase trajectory play out the same jökulhlaup physics from two complementary angles.