Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 6 12 2006 10.5194/acp-6-4117-2006 http://www.atmos-chem-phys.net/6/4117/2006/ http://www.atmos-chem-phys.net/6/4117/2006/acp-6-4117-2006.html http://www.atmos-chem-phys.net/6/4117/2006/acp-6-4117-2006.pdf 4117 4127 2006-09-13 Observations of lunar tides in the mesosphere and lower thermosphere at Arctic and middle latitudes D. J. Sandford d.j.sandford@bath.ac.uk H. G. Muller N. J. Mitchell Centre for Space, Atmospheric & Oceanic Science, Department of Electronic and Electrical Engineering, University of Bath, Bath, BA2 7AY, UK Meteor radars have been used to measure the horizontal winds in the mesosphere and lower thermosphere over Castle Eaton (52° N) in the UK and over Esrange (68° N) in Arctic Sweden. We consider a 16-year data set covering the interval 1988–2004 for the UK and a 6-year data set covering the interval 1999–2005 for the Arctic. The signature of the 12.42-h (M₂) lunar tide has been identified at both locations. The lunar tide is observed to reach amplitudes as large as 11 ms^−1. The Arctic radar has an interferometer and so allows investigation of the vertical structure of the lunar tide. At both locations the tide has maximum amplitudes in winter with a second autumnal maximum. The amplitude is found to increase with height over the 80–100 km height range observed. Vertical wavelengths are very variable, ranging from about 15 km in summer to more than 60 km in winter. Comparisons with the Vial and Forbes (1994) model reveals generally good agreement, except in the case of the summer vertical wavelengths which are observed to be significantly shorter than predicted. Beldon, C. L., Muller, H. G., and Mitchell, N. J.: The 8-hour tide in the mesosphere and lower thermosphere over the UK, 1988–2004, J. Atmos. Sol.-Terr. Phys., 68, 655–668, 2006. Chapman, S. and Lindzen R. S.: Atmospheric Tides: Thermal and Gravitational, 201 pp., D. Reidel Publishing Company Dorderecht – Holland, 1970. Luo, Y., Manson, A. H., Meek, C. E., Thayaparan, T., MacDougall, J., and Hocking, W. K.: The 16-day wave in the mesosphere and lower thermosphere: simultaneous observations at Saskatoon (52 degrees N, 107 degrees W) and London (43 degrees N, 81 degrees W), Canada, J. Atmos. Sol.-Terr. Phys., 64, 1287–1307, 2002. Malin, S. R. C. and Schlapp, D. M.: Geomagnetic Lunar Analysis by Least-Squares, Geophysical Journal of the Royal Astronomical Society, 60, 409–418, 1980. Mitchell, N. J., Williams, P. J. S., Beard, A. G., Buesnel, G. R., and Muller, H. G.: Non-linear planetary tidal wave interactions in the lower thermosphere observed by meteor radar, Ann. Geophys.-Atmospheres Hydrospheres And Space Sciences, 14, 364–366, 1996. Mitchell, N. J., Middleton, H. R., Beard, A. G., Williams, P. J. S., and Muller, H. G.: The 16-day planetary wave in the mesosphere and lower thermosphere, Ann. Geophys.-Atmospheres Hydrospheres And Space Sciences, 17, 1447–1456, 1999. Mitchell, N. J., Pancheva, D., Middleton, H. R., and Hagan, M. E.: Mean winds and tides in the Arctic mesosphere and lower thermosphere, J. Geophys. Res.-Space Phys., 107, 1004(A1), doi:10.1029/2001JA900127, 2002. Muller, H. G., Havill, R. L., Comley, V. E., and Hill, P. C. J.: A Study Of Meteor Radar Winds From 2 Locations In The British- Isles, J. Atmos. Terr. Phys., 57, 979–993, 1995. Murphy, D.J., Tsutsumi, M., Riggin, D. M., Jones, G. O. L., Vincent, R. A., Hagan, M. E., and Avery, S. K.: Observations of a nonmigrating component of the semidiurnal tide over Antarctica, J. Geophys. Res., 108(D8), 4241, doi:10.1029/2002JD003077, 2003. Palo, S. E., Roble, R. G., and Hagan, M. E.: Middle atmosphere effects of the quasi-two-day wave determined from a General Circulation Model, Earth Planets And Space, 51, 629–647, 1999. Pancheva, D., Merzlyakov, E., Mitchell, N. J., Portnyagin, Y., Manson, A. H., Jacobi, C., Meek, C. E., Luo, Y., Clark, R. R., Hocking, W. K., MacDougall, J., Muller, H. G., Kurschner, D., Jones, G. O. L., Vincent, R. A., Reid, I. M., Singer, W., Igarashi, K., Fraser, G. I., Fahrutdinova, A. N., Stepanov, A. M., Poole, L. M. G., Maliga, S. B., Kashcheyev, B. L., and Oleynikov, A. N.: Global-scale tidal structure in the mesosphere and lower thermosphere during the PSMOS campaign of June–August 1999 and comparisons with the global-scale wave model, J. Atmos. Sol.-Terr. Phys., 64, 1011–1035, 2002. Riggin, D. M., Meyer, C. K., Fritts, D. C., Jarvis, M. J., Murayama, Y., Singer, W., Vincent, R. A., and Murphy, D. J.: MF radar observations of seasonal variability of semidiurnal motions in the mesosphere at high northern and southern latitudes, J. Atmos. Sol.-Terr. Phys., 65, 483–493, 2003. Schlapp, D. M., Stening, R. J., Forbes, J. M., Manson, A. H., Meek, C. E., and Vincent, R. A.: N-2 and M(2) lunar tides: Atmospheric resonance revisited, Ann. Geophys.-Atmos. Hydrospheres Space Sci., 14, 826–836, 1996. Smith, A. K., Pancheva, D. V., and Mitchell, N. J.: Observations and modelling of the 6-hour tide in the upper mesosphere, J. Geophys. Res.-Atmos., 109, D10105, doi:10.1029/2003JD004421, 2004. Stening, R. J., Meek, C. E., and Manson, A. H.: Lunar Tidal Winds Measured In The Upper-Atmosphere (78–105 km) At Saskatoon, Canada, J. Atmos. Sci., 44, 1143–1151, 1987. Stening, R. J. and Vincent, R. A.: A Measurement Of Lunar Tides In The Mesosphere At Adelaide, South-Australia, J. Geophys. Res-Space Phys., 94, 10 121–10 129, 1989. Stening, R. J., Avery, S. K., and Tetenbaum, D.: Observations Of Lunar Tides In Upper-Atmosphere Winds At Poker Flat, Alaska, J. Atmos. Terr. Phys., 52, 715–721, 1990. Stening, R. J., Manson, A. H., Meek, C. E., and Vincent, R. A.: Lunar Tidal Winds At Adelaide And Saskatoon At 80 To 100 km Heights – 1985–1990, J. Geophys. Res-Space Phys., 99, 13 273–13 280, 1994. Stening, R. J., Forbes, J. M., Hagan, M. E., and Richmond, A. D.: Experiments with a lunar atmospheric tidal model, J. Geophys. Res.-Atmos., 102, 13 465–13 471, 1997a. Stening, R. J., Schlapp, D. M., and Vincent, R. A.: Lunar tides in the mesosphere over Christmas Island (2 degrees N, 203 degrees E), J. Geophys. Res.-Atmos., 102, 26 239–26 245, 1997b. Stening, R. J. and Jacobi, C.: Lunar tidal winds in the upper atmosphere over Collm, Ann. Geophys.-Atmos. Hydrospheres Space Sci., 18, 1645–1650, 2001. Stening, R. J., Tsuda, T., and Nakamura, T.: Lunar tidal winds in the upper atmosphere over Jakarta, J. Geophys. Res-Space Phys., 108(A5), 1192, doi:10.1029/2002JA009528, 2003. Teitelbaum, H. and Vial, F.: On Tidal Variability Induced by Nonlinear Interaction With Planetary Waves, J. Geophys. Res-Space Phys., 96, 14 169–14 178, 1991. Tsuda, T., Tanii, J., Aso, T., and Kato, S.: Lunar Tides At Meteor Heights, Geophys. Res. Lett., 8, 191–194, 1981. Vial, F. and Forbes, J. M.: Monthly Simulations Of The Lunar Semi-Diurnal Tide, J. Atmos. Terr. Phys., 56, 1591–1607, 1994. Winch, D. E. and Cunningham, R. A.: Lunar Magnetic Tides at Watheroo: Seasonal, Elliptic, Evectional, Variational and Nodal, J. Geomagnetism and Geoelectricity, 24, 381–414, 1972. Younger, P. T., Pancheva, D., Middleton, H. R., and Mitchell, N. J.: The 8-hour tide in the Arctic mesosphere and lower thermosphere, J. Geophys. Res-Space Phys., 107(12A), 1420, doi:10.1029/2001JA005086, 2002.