Size-dependent asymmetry of barchans indicates dune growth controlled by basal area or bulk volume

TY - JOUR

T1 - Size-dependent asymmetry of barchans indicates dune growth controlled by basal area or bulk volume

AU - Robson, Dominic T.

AU - Baas, Andreas C.W.

N1 - Publisher Copyright: © 2024 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.

PY - 2024/5/8

Y1 - 2024/5/8

N2 - We introduce a novel analytical model of the growth of barchan dunes in terms of their two flanks, from which we derive expressions for the size-dependence of the bilateral asymmetry of these bedforms in three cases where different mechanisms dominate the growth process. Analysis of the morphology of barchans on Mars and Earth suggest that there may exist two distinct attractor states for the asymmetry distribution. By comparing our analytical results with the observations, we show that the growth of barchan dunes appears to be dominated by processes, which are proportional to the basal area or volume of the bedforms, rather than being linear to their width as is typically assumed. We propose hypotheses explaining area-dominated growth as a result of variable wind regimes and volume-dominated growth from collisions. These predictions appear to be in line with the available data for the terrestrial swarms and barchan-like submarine bedforms and offer the potential of predicting patterns in inaccessible wind regimes from data on the morphology of the dunes.

AB - We introduce a novel analytical model of the growth of barchan dunes in terms of their two flanks, from which we derive expressions for the size-dependence of the bilateral asymmetry of these bedforms in three cases where different mechanisms dominate the growth process. Analysis of the morphology of barchans on Mars and Earth suggest that there may exist two distinct attractor states for the asymmetry distribution. By comparing our analytical results with the observations, we show that the growth of barchan dunes appears to be dominated by processes, which are proportional to the basal area or volume of the bedforms, rather than being linear to their width as is typically assumed. We propose hypotheses explaining area-dominated growth as a result of variable wind regimes and volume-dominated growth from collisions. These predictions appear to be in line with the available data for the terrestrial swarms and barchan-like submarine bedforms and offer the potential of predicting patterns in inaccessible wind regimes from data on the morphology of the dunes.

KW - aeolian geomorphology

KW - allometry

KW - asymmetry

KW - barchan

KW - dune

KW - modelling

UR - http://www.scopus.com/inward/record.url?scp=85192394026&partnerID=8YFLogxK

U2 - 10.1002/esp.5876

DO - 10.1002/esp.5876

M3 - Article

AN - SCOPUS:85192394026

SN - 0197-9337

VL - 49

SP - 3063

EP - 3072

JO - EARTH SURFACE PROCESSES AND LANDFORMS

JF - EARTH SURFACE PROCESSES AND LANDFORMS

IS - 10

ER -