Turbulence measurements with the micro-UAS SUMO - Technical developments and first applications

During the last 5 years, the Small Unmanned Meteorological Observer SUMO, a micro-UAS of 80 cm wingspan and 600 g take-off weight, has been developed as a new and flexible tool for atmospheric boundary layer (ABL) research. It can be operated as controllable and recoverable atmospheric sounding system for the lowest 4 km above the Earth's surface. In the year 2011 two main technical improvements of the system have been accomplished. The integration of an inertial measurement unit (IMU) into the Paparazzi autopilot system has expanded the environmental conditions for SUMO operation to now even allowing in-cloud flights. In the field of sensor technology, the implementation of a 5-hole probe for the determination of the 3 dimensional flow vector impinging the aircraft with a 100 Hz resolution have distinctly enhanced the meteorological measurement capabilities.

The extended SUMO version has in 2011 been operated during two field campaigns. The first one, in a wind farm close to Vindeby on Lolland, Denmark, was dedicated to the investigation of the effects of wind turbines on boundary layer turbulence. In spite of a few pitfalls related to configuration and synchronization of the corresponding data logging systems, this campaign provided promising results indicating the capability and future potential of small UAS for turbulence characterization in and around wind farms. The second one, the international BLLAST (Boundary Layer Late Afternoon and Sunset Transition) field campaign at the foothills of the Pyrenees in Lannemezan, France was focusing on processes related to the afternoon transition of the convective boundary layer. Here the SUMO turbulence system was flown to investigate the vertical structure of turbulence and its dependency on surface inhomogeneities.

The presentation will give a short overview on the technical development and first results from both campaigns.