boundary layer
From Glossary of Meteorology
- The layer of fluid near a boundary that is affected by friction against that boundary surface, and possibly by transport of heat and other variables across that surface.
In meteorology, this is the atmospheric boundary layer.
- In a physical or mathematical system, a region over which some property or term in the equations varies rapidly, that is, over its full range; conversely, a region outside of which certain terms may be neglected.