The boundary layer between a geostrophic flow and a solid boundary at which the no-slip condition applies.
In the geostrophic flow region, there is a uniform flow with velocity in the x direction. Associated
with
where is the rotational frequency, is the density. Now, look for a solution for the boundary with the velocity field uniform in the x and y directions. This is an ad hoc procedure, but is justified because such a solution exists. Take
This requires that
