Processor slang for the shape refraction errors take across a swath. When the applied sound speed is wrong, outer beams bend up (a smile) or down (a frown) relative to nadir, so a flat seabed looks like a dish or a dome on every ping. The fix is a better or more recent profile, or a refraction tool that bends the beams back during processing.
Whole afternoon's data is smiling, we missed the fresh water coming out on the ebb.
Also heard as
- smiley
- frowny
- refraction curl
Related terms
Refraction
The bending of sonar beams as they cross water layers with different sound speeds, which distorts depths if uncorrected.
SVP
Sound velocity profile: how the speed of sound changes with depth through the water, measured to correct sonar depths.
Cast
One lowering of a sound speed or CTD probe through the water column to measure a profile.
Bust
A vertical or horizontal mismatch between overlapping lines or surveys that exposes an error somewhere.