Extended Data Fig. 5: Changes in latitude–local time distribution of velocity associated with change in background velocity adopted in second estimation.

a–c, The background velocity is the sum of a rigid body rotation with an equatorial velocity of −95 m s⁻¹ and a constant offset of −15 m s⁻¹ (a), 0 m s⁻¹ (b) and 15 m s⁻¹ (c). Velocity vectors (top) and the meridional velocity (bottom) are shown. Each velocity vector is defined by the deviation of the zonal velocity from the local-time average and the total meridional velocity. Arrows are scaled such that the distance occupied by 10° in latitude represents a meridional speed of 5 m s⁻¹ and that occupied by 1 h in local time represents a zonal speed of 5 m s⁻¹.