Gravity waves in the mesopause region observed by meteor radar: 1. A simple measurement technique |
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| Authors: | NJ Mitchell CL Beldon |
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| Institution: | 1. S.K. Mitra Center for Research in Space Environment, University of Calcutta, 92, A.P.C. Road, Calcutta 700009, India;2. Institute of Radio Physics and Electronics, University of Calcutta, 92, A.P.C. Road, Calcutta 700009, India;1. Institute of Solar-Terrestrial Physics of Siberian Branch of Russian Academy of Sciences, Irkutsk, Russia;2. Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, Russia;3. Institute of Cosmophysical Research and Aeronomy of Siberian Branch of Russian Academy of Sciences, Yakutsk, Russia;4. Institute of Cosmophysical Researches and Radio Wave Propagation of the Far Eastern Branch of Russian Academy of Science, Paratunka, Russia;5. Institute of Geophysics of the Ural Branch of Russian Academy of Science, Ekaterinburg, Russia;6. Pushkov Institute of Terrestrial Magnetism Ionosphere and Radio Wave Propagation of Russian Academy of Science, Moscow, Russia;7. West Department of Pushkov Institute of Terrestrial Magnetism Ionosphere and Radio Wave Propagation of Russian Academy of Science, Kaliningrad, Russia;8. Leibniz Institute for Atmospheric Physics, Kühlungsborn, Germany;1. National Institute for Space Research, São José dos Campos, Sao Paulo, Brazil;2. Radar Space Sciences Laboratory, The Pennsylvania State University, 323 Electrical Engineering East, Pennsylvania, USA;3. Universidade Federal de Campina Grande, Campina Grande, Paraiba, Brazil;1. University of KwaZulu-Natal, School of Chemistry and Physics, Private Bag X54001, Durban 4000, South Africa;2. South Africa National Space Agency, PO Box 32, Hermanus 7200, South Africa;3. Department of Electronics and Electrical Engineering, University of Bath, Bath, UK;4. South Africa National Space Agency, PO Box 484, Silverton 0127, Gauteng, South Africa;1. Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, USA;2. Department of Physics, The Pennsylvania State University-Lehigh Valley, Center Valley, PA, USA |
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| Abstract: | A simple new technique for measuring gravity-wave activity using meteor radars is described. The technique uses the variance of horizontal wind velocities measured by individual meteors as a proxy for the activity of the gravity-wave field. It is sensitive to gravity waves with horizontal wavelengths of up to about 400 km and periods up to about 3 h. The technique can be used to investigate the vertical structure of the gravity-wave field at heights between approximately 80 and 100 km and with a time resolution of approximately 6 h. The technique is demonstrated using data from an all-sky meteor radar based at Rothera, Antarctica (68°S, 68°W). Observations made over Rothera for 2006 and 2007 reveal a seasonal behaviour with a semi-annual cycle in wave activity. Wave activity maximises in summer and winter and minimises at the equinoxes. Monthly mean gravity-wave activity increases with height in all seasons except in summer when gravity-wave variances show little or no increase with height below 90 km. Comparisons between the gravity-wave activity determined by this meteor-variance technique and other measurements at similar latitudes in the Antarctic reveal generally good agreement. |
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