Continuous measurements of time-varying free-surface profiles in aerated hydraulic jumps with a LIDAR

•Continuous measurements of time-varying free-surface profiles in hydraulic jumps.•Combined non-intrusive observations of free-surface fluctuations and jump toe oscillations.•Analysis of free-surface features in hydraulic jumps using free moving and fixed jump toe methods.•Identification of three characteristic regions in hydraulic jumps based upon characteristic frequencies.•LIDAR validated as an instrument to measure free-surface features in complex air-water flows non-intrusively.