Dipolar vortices generated by a force applied to an area of finite size are investigated in a rotating, polar β-plane fluid. The laboratory polar β-plane is dynamically equivalent to the polar regions of the ocean or the atmosphere where the Coriolis parameter varies quadratically with latitude. Both forced and unforced evolution of the flow is observed. The altimetric imaging velocimetry method is employed for imaging the rotating flows and measuring the velocity and surface elevation fields. The forced dipoles were observed to rotate in the anticyclonic direction from their initial orientation where the axis of the dipole is aligned with the direction of the force toward some steady state where the axis of the dipole is at an angle to the direction of the force. The theoretical prediction of the rotation angle is found to be in good agreement with the experimental results. Asymptotic solutions for limiting cases when forced dipoles are affected either by the Ekman-type bottom friction or by the γ-effect are found. The experiments also demonstrate that the unforced free dipoles rotate anticyclonically with almost steady rate and emit basin-scale Rossby waves.

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