As part of the VALUAS project, small unmanned research aircraft are used to collect high-resolution turbulence data in space and time. This in-situ measurement data and the resulting atmospheric boundary layer characteristics will be used to evaluate and assess lidar systems and the DWD's numerical model ICON.
VALUAS will evaluate the quality, spatial resolution and significance of data from single lidar systems and several combined systems. The different scanning methods, different locations and different atmospheric conditions (e.g. thermal stratification, water vapor content, number of concentrations and size distribution of particles, clouds) will be considered. This allows suitable lidar scanning strategies to be determined and precise measurement errors, as well as the representativeness and availability of lidar wind and turbulence data, to be quantified. VALUAS provides the DWD with a suitable tool to better integrate remote sensing instruments into the operational measurement network and to better assess the performance and availability of lidar systems under different atmospheric conditions.

At the same time, the measurement database created in VALUAS is used for the evaluation of numerical simulations of the DWD, such as the high-resolution ICON-LES, and the mesoscale ICON and its boundary layer parameterization. In cooperation with the Goethe University Frankfurt (boundary layer meteorology at the Institute for Atmosphere and Environment), the performance of ICON in critical transition phases, such as between stable and unstable thermal layers (morning and late afternoon), is assessed and the boundary layer parameterization is improved, especially for diabatic processes in the model.