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Dynamic allometry in coastal overwash morphology

Authors :
Ana Matias
Kirstin L. Davenport
Eli D. Lazarus
Source :
Repositório Científico de Acesso Aberto de Portugal, Repositório Científico de Acesso Aberto de Portugal (RCAAP), instacron:RCAAP, Earth Surface Dynamics, Vol 8, Pp 37-50 (2020)
Publication Year :
2020
Publisher :
Copernicus GmbH, 2020.

Abstract

Allometry refers to a physical principle in which geometric (and/or metabolic) characteristics of an object or organism are correlated to its size. Allometric scaling relationships typically manifest as power laws. In geomorphic contexts, scaling relationships are a quantitative signature of organization, structure, or regularity in a landscape, even if the mechanistic processes responsible for creating such a pattern are unclear. Despite the ubiquity and variety of scaling relationships in physical landscapes, the emergence and development of these relationships tend to be difficult to observe - either because the spatial and/or temporal scales over which they evolve are so great or because the conditions that drive them are so dangerous (e.g. an extreme hazard event). Here, we use a physical experiment to examine dynamic allometry in overwash morphology along a model coastal barrier. We document the emergence of a canonical scaling law for length versus area in overwash deposits (washover). Comparing the experimental features, formed during a single forcing event, to 5 decades of change in real washover morphology from the Ria Formosa barrier system, in southern Portugal, we find differences between patterns of morphometric change at the event scale versus longer timescales. Our results may help inform and test process-based coastal morphodynamic models, which typically use statistical distributions and scaling laws to underpin empirical or semi-empirical parameters at fundamental levels of model architecture. More broadly, this work dovetails with theory for landscape evolution more commonly associated with fluvial and alluvial terrain, offering new evidence from a coastal setting that a landscape may reflect characteristics associated with an equilibrium or steady-state condition even when features within that landscape do not. Funding Agency NERC Natural Environment Research Council NE/N015665/2 Leverhulme Trust RPG-2018-282 info:eu-repo/semantics/publishedVersion

Details

ISSN :
2196632X
Volume :
8
Database :
OpenAIRE
Journal :
Earth Surface Dynamics
Accession number :
edsair.doi.dedup.....51aa309e879d3b69e1b8efd5ca48b536
Full Text :
https://doi.org/10.5194/esurf-8-37-2020