Average time between events when the Shields parameter exceeds 0.25

This data represents the average time between events when the Shields parameter (Shields, 1936) exceeds 0.25 based on a Peaks-Over-Thresholds (POT) analysis. The Shields parameter (non-dimensional bed shear stress) value of 0.25 is assumed to be the threshold for creating disturbed patches. This value is several times larger than that required to initiate traction bedload transport (~0.05) and falls in the middle of the ripple and dune bedform stability field. It represents conditions when the seabed is highly mobile and where patches of disturbed habitat are likely to be created. The unit for the dataset is day.
Shields, A. 1936. Application of similarity principles and turbulence research to bed-load movement. Mitteilunger der Preussischen Versuchsanstalt f'ur Wasserbau und Schiffbau 26: 5-24