ABSTRACT
As the earth’s surface is approached, the frictional forces play an important role in the balance of forces on the moving air. For larger storms such as extra-tropical depressions, this zone extends up to 500-1000-m height. For thunderstorms, the boundary layer is much smaller – probably around 100 m (see Section 3.2.5). The region of frictional influence is called the ‘atmospheric boundary layer’ and is similar in many respects to the turbulent boundary layer on a flat plate or airfoil at high wind speeds.
