A) Surface topography map of one-layer SW simulations at the equatorial region under Jovian conditions when zonal winds are turned off and disturbance amplitude is 3 m and L_E = 5000 km. A pair of Rossby–Kelvin wave forms resembling the Matsuno-Gill model. From the point of view of the injected pulse, Rossby waves (double symmetric lobe at left) drift to the west,while the Kelvin wave (large bar at right) moves to the east (c_K = 108 m s^-1). B) Surface topography map for the same conditions as in panel A) (L_E and initial perturbation amplitude), when zonal winds are switched on. In this case c_K = 187 m s^-1, which is very close to the sum of background zonal wind speed and theoretical velocity phase for the Kelvin wave.