Two-dimensional zonal wind fields derived from ALMA observations in 2016 (Ls = 82°) and 2017 (Ls = 90°). Peak-normalized emission contribution functions for each molecule (from Lellouch et al. 2019) are shown for 2016 (top-right x-axis) using colored curves. Wind speeds have been linearly interpolated between the peak contribution altitudes (﹩\bar{z}﹩) for the respective molecules, and are assumed constant outside the interpolation range (345–990 km).