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Back to Einstein: Burial‐Induced Three‐Range Diffusion in Fluvial Sediment Transport
Author(s) -
Pierce J. Kevin,
Hassan Marwan A.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl087440
Subject(s) - bed load , tracer , diffusion , fluvial , geology , range (aeronautics) , sediment transport , random walk , sediment , rest (music) , anomalous diffusion , geomorphology , physics , innovation diffusion , materials science , computer science , statistics , mathematics , structural basin , nuclear physics , acoustics , composite material , thermodynamics , knowledge management
Individual grains move through gravel bed rivers in cycles of motion and rest, so tracer grains diffuse as they transport downstream. Tracer experiments demonstrate at least three diffusion ranges as observation times increase, with different spreading rates in each range. Until now, the generating processes of these ranges have remained unclear. In this work, we develop a random walk model of individual bedload trajectories including motion, rest, and burial processes. The model describes three bedload diffusion ranges that terminate in a fourth nondiffusive range when all tracers become buried. Using the model, we attribute three‐range tracer diffusion to the interplay between motion, rest, and burial processes, and we relate the multirange diffusion characteristics to the timescales of these processes.