A Lagrangian Vortex Method for the Barotropic Vorticity Equation on a Rotating Sphere

We present a Lagrangian vortex method for the barotropic vorticity equation on a rotating sphere. The method solves for the flow map using Lagrangian particles and panels. The velocity is computed by evaluating the Biot-Savart integral on the sphere. An adaptive refinement strategy is implemented to maintain accuracy over long times. Results are presented for propagating Rossby-Haurwitz waves and localized vortex interactions.