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Beach slopes from satellite-derived shorelines
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  • Kilian Vos,
  • Mitchell Dean Harley,
  • Kristen Splinter,
  • Andrew Walker,
  • Ian L. Turner
Kilian Vos
UNSW Water Research Laboratory, UNSW Water Research Laboratory

Corresponding Author:[email protected]

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Mitchell Dean Harley
University of New South Wales, University of New South Wales
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Kristen Splinter
UNSW Water Research Laboratory, UNSW Water Research Laboratory
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Andrew Walker
University of New South Wales, University of New South Wales
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Ian L. Turner
University of New South Wales, University of New South Wales
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Abstract

The steepness of the beach face is a fundamental parameter for coastal morphodynamic research. Despite its importance, it remains extremely difficult to obtain reliable estimates of the beach-face slope over large spatial scales (1000’s of km of coastline). In this letter, a novel approach to estimate this slope from time-series of satellite-derived shoreline positions is presented. This new technique uses a frequency-domain analysis to find the optimum slope that minimises high-frequency tidal fluctuations relative to lower-frequency erosion/accretion signals. A detailed assessment of this new approach at 8 locations spanning a range of tidal regimes, wave climates and sediment grain sizes shows strong agreement (R = 0.9) with field measurements. The automated technique is then applied across 1000’s of beaches in eastern Australia and California USA, revealing similar regional-scale distributions along these two contrasting coastlines and highlights the potential for new global-scale insight to beach-face slope spatial distribution, variability and trends.
28 Jul 2020Published in Geophysical Research Letters volume 47 issue 14. 10.1029/2020GL088365