[1] We present zonal and meridional wind measurements at three altitude levels within the cloud layers of Venus from cloud tracking using images taken with the VIRTIS instrument on board Venus Express. At low latitudes, zonal winds in the Southern hemisphere are nearly constant with latitude with westward velocities of 105 ms À1 at cloudtops (altitude $ 66 km) and 60-70 ms À1 at the cloud-base (altitude $ 47 km). At high latitudes, zonal wind speeds decrease linearly with latitude with no detectable vertical wind shear (values lower than 15 ms À1 ), indicating the possibility of a vertically coherent vortex structure. Meridional winds at the cloud-tops are poleward with peak speed of 10 ms À1 at 55°S but below the cloud tops and averaged over the South hemisphere are found to be smaller than 5 ms À1. We also report the detection at subpolar latitudes of wind variability due to the solar tide.

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