surface boundary layer
Also found in: Acronyms.
surface boundary layer[′sər·fəs ′bau̇n·drē ‚lā·ər]
That thin layer of air adjacent to the earth's surface, extending up to the so-called anemometer level (the base of the Ekman layer); within this layer the wind distribution is determined largely by the vertical temperature gradient and the nature and contours of the underlying surface, and shearing stresses are approximately constant. Also known as atmospheric boundary layer; friction layer; ground layer; surface layer.