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Evaluating landscape complexity and the contribution of non‐locality to geomorphometry

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journal contribution
posted on 30.03.2021, 10:37 by Chris KeylockChris Keylock, A Singh, P Passalacqua, E Foufoula‐Georgiou
A long-standing question in geomorphology concerns the extent that statistical models of terrain elevations have adequate characteristics with respect to the known scaling properties of landscapes. In previous work, it has been challenging to ascribe statistical significance to metrics adopted to measure landscape properties. In this paper, we use a recently developed surrogate data algorithm to generate synthetic surfaces with identical elevation values to the source dataset, while also preserving the value of the H¨older exponent at any point (the underpinning characteristic of a multifractal surface). Our primary source data are from a laboratory experiment on landscape evolution. This allows us to examine how the statistical properties of the surfaces evolve through time and the extent to which they depart from the simple (multi)fractal formalisms. We show that there is a strong departure that is driven by the diffusive processes in operation. The number of sub-basins of a given channel order (for orders sufficiently small relative to the basin order) exhibit a clear increase in complexity after a steady-state for sediment flux is established. We also study elevation data from Florida and Washington State where the relative departure from simple multifractality is even more strongly expressed but is similar for two very different locations. Our results show that at the very least, the minimum complexity for a stochastic model for terrain statistics with appropriate geomorphic scalings needs to incorporate a conditioning between the pointwise H¨older exponents and elevation.

Funding

Royal Academy of Engineering/Leverhulme Trust Senior Research Fellowship LTSRF1516-12-89

NSF (grants EAR-1811909 and ECCS-1839441)

History

School

  • Architecture, Building and Civil Engineering

Published in

Journal of Geophysical Research: Earth Surface

Volume

126

Issue

4

Citation

Keylock, C. ... et al. ,(2021), Evaluating landscape complexity and the contribution of non‐locality to geomorphometry, Journal of Geophysical Research: Earth Surface, 126, 4, DOI: 10.1029/2020jf005765

Publisher

American Geophysical Union (AGU)

Version

AM (Accepted Manuscript)

Rights holder

© American Geophysical Union

Publisher statement

An edited version of this paper was published by AGU. Copyright (year) American Geophysical Union. Accepted for publication in Journal of Geophysical Research: Earth Surface. Copyright (year) American Geophysical Union. To view the published open abstract, go to http://dx.doi.org and enter the DOI.

Acceptance date

14/03/2021

Publication date

2021-04-18

Copyright date

2021

ISSN

2169-9003

eISSN

2169-9011

Language

en

Depositor

Prof Chris Keylock. Deposit date: 25 March 2021

Article number

e2020JF005765