Airborne temperature profiling in he troposphere during daytime by lidar utilizing Rayleigh-Brillouin scattering

The airborne measurement of a temperature profile from 10.5 km down towards ground (approximate to 1.4 km above sea level) during daytime by means of a lidar utilizing Rayleigh-Brillouin (RB) scattering is demonstrated for the first time, to our knowledge. The spectra of the scattered light were measured by tuning the laser (lambda = 354.9 nm) over a 11 GHz frequency range with a step size of 250 MHz while using a Fabry-Perot interferometer as a spectral filter. The measurement took 14 min and was conducted over a remote area in Iceland with the ALADIN Airborne Demonstrator on-board the DLR Falcon aircraft. The temperature profile was derived by applying an analytical RB line shape model to the backscatter spectra, which were measured at different altitudes with a vertical resolution of 630 m. A comparison with temperature profiles from radiosonde observations and model temperatures shows reasonable agreement with biases of less than +/- 2 K. Based on Poisson statistics, the random error of the derived temperatures is estimated to vary between 0.1 K and 0.4 K. The work provides insight into the possible realization of airborne lidar temperature profilers based on RB scattering. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.