Coastal profile evolution at Duck, North Carolina: A cautionary note

The Hurst exponents of 10.8-year-long time series of cumulative bed level o bserved between the shoreline and similar to 8-m water depth on an ocean be ach are shown to be consistent with bed-level time series described by a si nusoid with a 10.8-year period plus white noise. Thus, for these observatio ns, Hurst exponents cannot distinguish self-organized morphological evoluti on from the hypothesis that nearshore morphology on monthly to decadal time scales is a forced response to small-scale physical processes driven by wav es and currents.