Fig. 5From: Atmospheric Kelvin–Helmholtz billows captured by the MU radar, lidars and a fish-eye cameraa (Left) solid lines: MU radar-derived wind profiles averaged over 30 min (0557–0627 LT). Dotted lines: the corresponding profiles measured by the radiosonde about 1 h after. The altitudes are shifted upward by + 0.5 km in order to compensate for the altitude variations of the frontal layer. (Middle and right): the corresponding wind shears and wind shear directions. Circles are shear directions indicated by the MU radar. b Wind and shear vectors around the critical level according to the radar and balloon dataBack to article page