Abstract
Arctic tidal currents with periods near the local inertial period are strongest and rotate clockwise at mid-depth, and decrease in amplitude towards the bottom and ice-cover, experiencing a change in direction of rotation of the current vector to counterclockwise near the boundaries. Such observations are explained by analytical solutions to a simple model in which the current vector of frequency ω is the sum of oppositely rotating components. The frictional boundary layer thickness is proportional to (ω±f)−1, and therefore is markedly different for the two components. In the case of semidiurnal tidal components at high latitudes, the positive rotary component has a thin boundary layer and dominates near the boundaries, whereas the negative rotary component with a much larger boundary layer dominates at mid-depth. For a two-layered ocean, a set of particular solutions is used to verify the observed vertical variations in velocity components with maxima occurring at the interface between the two layers (pycnocline). A general solution consisting of the sum of particular and homogeneous solutions is also presented for the condition when the maxima in velocity components occurs away from the interface.
