What sets aeolian dune height?

Autor: Gunn A; School of Earth Amtosphere and Environment, Monash University, Clayton, Australia.; Department of Geological Sciences, Stanford University, Palo Alto, USA.; Department of Earth and Environmental Sciences, University of Pennsylvania, Philadelphia, USA., Casasanta G; Institute of Atmospheric Sciences and Climate - National Research Council of Italy (CNR-ISAC), Rome, Italy., Di Liberto L; Institute of Atmospheric Sciences and Climate - National Research Council of Italy (CNR-ISAC), Rome, Italy., Falcini F; Institute of Marine Science - National Research Council of Italy (CNR-ISMAR), Rome, Italy., Lancaster N; Earth & Ecosystem Sciences, Desert Research Institute, Reno, USA., Jerolmack DJ; Department of Earth and Environmental Sciences, University of Pennsylvania, Philadelphia, USA. sediment@sas.upenn.edu.; Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, USA. sediment@sas.upenn.edu.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2022 May 03; Vol. 13 (1), pp. 2401. Date of Electronic Publication: 2022 May 03.
DOI: 10.1038/s41467-022-30031-1
Abstrakt: Wherever a loose bed of sand is subject to sufficiently strong winds, aeolian dunes form at predictable wavelengths and growth rates. As dunes mature and coarsen, however, their growth trajectories become more idiosyncratic; nonlinear effects, sediment supply, wind variability and geologic constraints become increasingly relevant, resulting in complex and history-dependent dune amalgamations. Here we examine a fundamental question: do aeolian dunes stop growing and, if so, what determines their ultimate size? Earth's major sand seas are populated by giant sand dunes, evolved over tens of thousands of years. We perform a global analysis of the topography of these giant dunes, and their associated atmospheric forcings and geologic constraints, and we perform numerical experiments to gain insight on temporal evolution of dune growth. We find no evidence of a previously proposed limit to dune size by atmospheric boundary layer height. Rather, our findings indicate that dunes may grow indefinitely in principle; but growth depends on morphology, slows with increasing size, and may ultimately be limited by sand supply.
(© 2022. The Author(s).)
Databáze: MEDLINE
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