Rarefied particle motions on hillslopes – Part 4: Philosophy

Abstract. Theoretical and experimental work (Furbish et al., 2021a, b, c) indicates that the travel distances of rarefied particle motions on rough hillslope surfaces are described by a generalized Pareto distribution. The form this distribution varies with balance between gravitational heating due to conversion potential kinetic energy frictional cooling particle–surface collisions. in problem is maximum entropy constrained fixed energetic “cost” – total cumulative extracted collisional friction per unit available during motions. analyses leading these results provide an ideal case study for highlighting three key elements statistical mechanics framework describing sediment transport: merits probabilistic versus deterministic descriptions motions, implications continuum transport conditions, consequences increasing uncertainty accompany length scales timescales. We use extraction, spatial evolution states, method applied as examples illustrate mechanistic yet nature approach. These highlight idea endeavor not simply about adopting theory or methods “off shelf” but rather involves appealing style thinking while tailoring analysis process scale interest. Under flux its divergence pertain ensemble conditions involving possible outcomes, each realization being compatible controlling factors. When factors change over time, individual outcomes reflect legacy earlier depends rate relative intermittency implication landform configurations associated fluxes inherent variability (“weather”) just important expected (“climate”) characterizing system behavior.