(
2005-01-14)
Gallagher, E. L.; Elgar, Steve; Guza, R. T.; Thornton, Ed B.
Estimates of the heights of large (0.1-0.4 m heights and 1-10 m horizontal
lengths) migrating bedforms on a sandy beach made with fixed, single-point altimeters are
similar to heights estimated from profiles across the bedforms made with altimeters mounted
on an amphibious vehicle that traversed the surf zone. Unlike many profiling systems, the
robust, fixed altimeters can measure bedforms in bubbly, sediment-laden surfzone waters
nearly continuously, including during storms, thus allowing investigation of the relationships
between bedform heights and near-bottom velocities to be extended to a wide range of wave
conditions. The fixed-altimeter observations of migrating bedforms suggest a sandy surfzone
seafloor is not always smooth during energetic conditions with strong mean currents and large
wave-orbital velocities.
