SUMO - Small Unmanned Meteorological Observer

The knowledge of the structure of the lower atmosphere, especially with respect to temperature, humidity and wind, is the key for the understanding of processes in the Atmospheric Boundary Layer (ABL). Up to now there is a lack of affordable measurement systems, applicable for ABL phenomena with horizontal scales between 100 m up to 10 km. During the past years a corresponding profiling system (KALI) has been developed at the University of Munich, on the basis of a remotely piloted vehicle (RPV). Enabling measurements of the atmosphere up to heights of more than 2 km above ground, as well as horizontal soundings at different levels, KALI has successfully been used during several field experiments in Nepal, Bolivia and Germany.

Remotely piloted vehicle KALI for the measurement of temperature and humidity profiles in the atmospheric boundary layer. The picture is taken during the campaign JUIPIT'AYA at Salar de Uyuni, Bolivia. The system is based on an electric powered model aircraft that allows measurements up to 2500 m above ground.

View from above onto KALIs fuselage with dismounted wings. It shows the matchbox sized data logger (upper center), and the meteorological onboard sensors for pressure (upper left beside the battery) and temperature and humidity (shielded by the small tubes attached by tape to the outside of the fuselage).

During a 4 year PhD-project at the Geophysical Institute, University of Bergen, the RPV's sensor technology will be upgraded and expanded. The focus will be set on the development, installation and evaluation of a system for measurements of wind speed and wind direction onboard. For this new small unmanned meteorological observer (SUMO) the flow measurements made onboard the RPV have to be combined with information on ground speed (derived by a GPS system) and information on the orientation of the plane referring to the North direction. Feasibility studies in cooperation with the University of Applied Sciences (UAS) at Regensburg, Germany, resulted in two promising approaches, applicable for flow measurements onboard KALI. A thermistor anemometer or a combination of miniaturized wind wheel and vane are supposed to satisfy the special requirements on size and weight given by the RPV. This part of the work will be done in close cooperation with the University of Applied Sciences, Regensburg, Germany, including laboratory wind tunnel tests. In addition we are working on the replacement of the recent 8-bit data logging by a higher precision system on the basis of free programmable micro-controllers.

First outdoor test of the miniaturized anemometer (maybe the worlds smallest) intended for flow determination onboard SUMO. It is intended to be fixed on one of the airplanes wing tips. The anemometer is a combination of a slightly modified commercial flow sensor (Schiltknecht) and a self constructed angle decoder.

Another focus of the project is set to improve the RPV's suitability for the intended operation in polar environments. The actual version of KALI has already been designed for flights in harsh environmental conditions. It has successfully been used in the presence of strong and turbulent winds up to 30 m/s and low temperatures in mountainous regions of the Nepalese Himalayas and the Bolivian Andes with starting altitudes up to 5000 m a.s.l. Nevertheless adaptations will be necessary for secure operation in the extreme atmospheric conditions due to polar climates. The functionality has to be assured down to temperatures of -40°C. Additionally, if started at costal sites, from research vessels or at oil platforms, at least temporary floatage has to be assured to enable emergency recovery of SUMO from the sea.

Project members:
Dr. Joachim Reuder, Project leader, University of Bergen, Norway
Stephan Lämmlein, Professor, University of Applied Sciences, Regensburg, Germany
Tor de Lange, Technician, University of Bergen, Norway
Stefan Kneifel, Student assistant, University of Bergen, Norway
Stephanie Mayer, PhD student, University of Bergen, Norway
Wolfgang Schäper, Electronic Engineer, Germany
Jan Schween, PostDoc, University of München, Germany
Meinhard Seefeldner, Engineer, University of München, Germany