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.