Fine Structure of the Stably Stratified Atmospheric Boundary Layer in Antarctica
Final Report Abstract
The results of this project are based on a unique measurement campaign which employed the first two meteorological unmanned aerial vehicles (M2AV) on the Antarctic ice-shelf at Halley station. The field campaign was carried out in cooperation of the Institut für Luft- und Raumfahrtsysteme, Technische Universität Braunschweig (ILR), and the British Antarctic Survey (BAS). The measurement campaign started in November 2006 and ended in December 2007. Due to unusual bad weather conditions at Halley in the summer and autumn 2007, this period was mainly used for tests and modifications of the systems for very cold temperatures. The meteorological flights finally started in the end of October, 2007. In total 20 flights were performed from which 4 were off-base and partly over sea ice. The on-siteflights were performed at Halley station near a sodar and a 32 m-tower. The off-base flight were perfonmed at Windy Bay, crossing the shelf-ice edge. For this project the wind measurements wilh the M2AV had to be improved. An in-flight wind calibration technique was developed that corrects for the inaccuracy of the true heading, the constant offset of the pitch angle and the underestimation of the true airspeed. The finally adjusted wind measurements were verified during two field experiments: 1. the M2AV inter-comparison campaign at the measurement field of the German Meteorological Service, South-East of Berlin (DWD-2007), 2. the M2AV flights in the stable boundary layer over shelf-ice at Halley V station, Antarctica (HalIey-2007). The airborne-measured wind vector agreed very well with the available ground-based and remote sensing measurements at the flight location for both the convective and stable boundary layer. Additionally, the absolute and relative accuracy of temperature, humidity and the wind vector of the flight measurements was defined. Turbulent heat fluxes and the turbulent structure parameter for temperature C2T were calculated during the DWD-2007 and during two flights of the Halley-2007 campaign. For a more accurate calculation of in situ C2T and sensible heat flux H, a faster temperature sensor aboard the M2AV is required; particularly for measurements in the (polar) stable boundary layer where the turbulent fluctuationsare very small. The project reached its aims only in parts. But the experienced obtained especially under extreme environmental conditions gave large impulse for improved and enhanced data-analysis strategies, airborne wind-vector calibration and for future airborne sensor development.
Publications
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2007: Boundary layer measurements with the autonomous mini-UAV M2AV. In: Deutsch - Österreichisch - Schweizerische Meteorologen - Tagung, Deutsche Meteorologische Gesellschaft, Hamburg, Germany, p. 10 pp
van den Kroonenberg, A. C., Spieß, T., Buschmann, M., Martin, T., Anderson, P. S., Beyrich, F. and Bange, J.
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2007: First Application of the Meteorological Mini-UAV 'M2AV'. Meteorol. Z. N. F., 16(2), 159-169
Spieß, T., Bange, J., Buschmann, M. and Vörsmann, P.
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2007: Probing the atmospheric boundary layer with the Meteorological UAV 'M2AV Carolo'. In: 7th Annual Meeting of the European Meteorological Society, EMS, San Lorenzo de El Escorial, Spain
van den Kroonenberg, A. C., Spieß, T., Martin, T. and Bange, J.
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2007: Turbulent Flux Calculation in the Polar Stable Boundary Layer: Multiresolution Flux Decomposition and Wavelet Analysis. J. Geophys. Res., 112, 12 pp
van den Kroonenberg, A. C. and Bange, J.
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2008: First wind measurements with the Meteorological UAV 'M2AV Carolo'. In: 18th Symposium on Boundary Layers and Turbulence, American Meteorological Society, Stockholm, Sweden, p. 9
van den Kroonenberg, A. C., Spieß, T. and Bange, J.
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2008: Measuring the Wind Vector Using the Autonomous Mini Aerial Vehicle M2AV. J. Atmos. Oceanic Technol., 25(11), 1969-1982
van den Kroonenberg, A. C., Martin, T., Buschmann, M., Bange, J. and Vörsmann, P.
