Theoretical development of an operational wave-induced ice erosion model through laboratory experiments

Abstract

Wave-induced melting of vertical ice fronts is represented in several operational iceberg and coastal-erosion models by the rough-wall parameterization of White (1980), whose closure chain is incompletely documented and whose commonly used compact expression is stated at the waterline. We reconstruct the formulation, specify the rough-turbulent wave-friction closure using Jonsson's implicit relation and its Lambert-W solution, and extend the model to a depth-resolved melt-rate profile under linear wave kinematics. Because the horizontal and vertical orbital-velocity components are linked, we use the horizontal component as a convenient representative scale and introduce a dimensionless coefficient alpha for the remaining closure uncertainty. The reconstruction gives a waterline coefficient of 3.0 x 10^-4 with White's resultant-velocity definition and 2.09 x 10^-4 for the reference choice alpha = 1; neither reproduces White's published 1.46 x 10^-4 directly. Two monochromatic wave-flume experiments with freshwater ice are then used to calibrate alpha from profiles below the wave trough. The full Lambert-W friction coefficient is used in this calibration. Best-fit values are 0.684 and 0.612 for periods of 1.54 and 0.87 s, respectively, a relative difference of approximately 11%. Their corresponding effective waterline coefficients, 1.43 x 10^-4 and 1.28 x 10^-4, are close to White's published value but do not constitute an independent validation. The fitted profiles reproduce the observed depth dependence below the trough, while deviations near the surface expose unresolved effects of intermittent submergence, local wave impact, and uncertain thermal forcing.