Correction of sonic anemometer angle of attack errors |
| |
| Institution: | 1. CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan;2. Institute of Low Temperature Science, Hokkaido University, N19 W8, Kita-Ku, Sapporo 060-0819, Japan;3. Department of Hydrology and Geo-Environmental Sciences, Faculty of Earth and Life Sciences, Vrije Universiteit, de Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands;4. Centre for Ecology and Hydrology, Wallingford OX10 8BB, UK;1. Institute of Ecology, University of Innsbruck, Innsbruck, Austria;2. Environmental Protection Agency of Aosta Valley, ARPA VdA, Climate Change Unit, Aosta, Italy;1. Department for Innovation in Biological Agro-food and Forest systems, University of Tuscia, Viterbo, Italy;2. Department of Biosystem Engineering, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium;3. Department of Environmental Sciences, University of Basel, Basel, Switzerland;4. Department of Earth and Ecosystem Sciences, Lund University, Lund, Sweden;5. Department of Hydrosciences, Technische Universität Dresden, Dresden, Germany;6. Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden;7. Faculty of Science and Technology, Free University of Bolzano, Bolzano, Italy;8. Forest Services, Autonomous Province of Bolzano, Bolzano, Italy;9. Helmholtz Centre for Environmental Research UFZ, Germany;10. CMCC Euro Mediterranean Centre on Climate Change, IAFES Division, Viterbo, Italy;1. Key Laboratory of Urban Underground Engineering of Ministry of Education, Beijing Jiaotong University, Beijing, China;2. Qinghai Research and Observation Base, Key Laboratory of Highway Construction & Maintenance Technology in Permafrost Regions, Ministry of Transport, Xining, Qinghai, China;1. Department of Mechanical & Aerospace Engineering, Naval Postgraduate School, Monterey, CA 93943, USA;2. Department of Mechanical Engineering, US Naval Academy, Annapolis, MD 21402, USA |
| |
| Abstract: | An improved method of correcting for the angle of attack error resulting from the imperfect (co)sine response of ultrasonic anemometers is proposed. The angle of attack, which was calculated as the arctangent of observed wind vectors, contains the angle of attack errors in the vectors themselves, and hence this angle was ‘false’. The ‘true’ angle of attack should be calculated from the corrected or ‘true’ wind vectors. In the improved method, the ‘true’ angle of attack is derived by solving a nonlinear equation which connects the ‘false’ angle of attack to the ‘true’ one. In applying this method to the case of R2- and R3-type Solent ultrasonic anemometers, the fit of the function for the sine responses to wind tunnel data was improved, and the cosine response function was also improved to consider the effect of the difference of the vertical positions of the transducers. The nonlinear equation was solved using the Steffensen method; robustly and adequately fast for practical use in calculating eddy fluxes. The accuracy of the correction method is improved over a previous one, especially at large angles of attack. Applying our correction method to field data from two forests and one peat bog, the eddy fluxes of sensible heat, latent heat and CO2were increased and the energy balance closure rates were improved. These results indicate that a large portion of energy imbalance can be accounted for by the ultrasonic anemometer angle of attack dependent errors. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
