An experimental study of homogeneous lenses in a stratified rotating fluid

Injection of a homogeneous fluid into a linearly stratified and rotating background fluid produced anticyclonic lenses which were studied for up to 600 rotation periods. Velocity measurements showed that the interior core rotates as a solid body with a decreasing, nearly axisymmetric exterior velocity field. Gill's (1981) model predicts well both the velocity and aspect ratio vs. Rossby number of the lenses. Lens decay occurred in two stages: symmetric rapid spin-down, with an associated half-life of ≈ 70 rotation periods followed by asymmetric shedding at a nearly constant core Rossby number, Ro ≈ 0.06.