The vertical and horizontal distributions of aeolian mass flux were measured on arnsandy beach using compartmented sediment traps. Numerical modeling of saltation trajectoriesrnwas used to reconstruct the measured distributions. It was found that the modeling approachrncould generate a good approximation of the field data across a wide range of friction velocities.rnHowever, in contrast to most previous conceptualizations of the process, best results werernobtained with the mean grain mean launch speed held constant, independent of friction velocity.rnThis was interpreted to indicate that the bed response to saltation impacts is conceptually similarrnto a plastic limit, so that additional impact energy associated with higher wind speeds isrnexpended in bed deformation rather than higher, longer saltation trajectories. Examination of thernmass-flux distributions of individual sediment size-fractions provided additional support for thisrnhypothesis, in the finding that these distributions were well-represented by simulations thatrnemployed mean launch speeds scaled to a constant kinetic energy level at launch for each grainrnsize.
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