ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-11-4149-2011 Aura MLS observations of the westward-propagating <i>s</i>=1, 16-day planetary wave in the stratosphere, mesosphere and lower thermosphere Day K. A. 1 Hibbins R. E. 2 3 Mitchell N. J. 1 Centre for Space, Atmospheric and Oceanic Science, Department of Electronic and Electrical Engineering, The University of Bath, BA2 7AY, UK British Antarctic Survey, Cambridge, CB3, 0ET, UK Department of Physics, Norwegian University of Science and Technology, (NTNU), Trondheim, Norway 05 05 2011 11 9 4149 4161 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/11/4149/2011/acp-11-4149-2011.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/4149/2011/acp-11-4149-2011.pdf

The Microwave Limb Sounder (MLS) on the Aura satellite has been used to measure temperatures in the stratosphere, mesosphere and lower thermosphere. The data used here are from August 2004 to December 2010 and latitudes 75° N to 75° S. The temperature data reveal the regular presence of a westward-propagating 16-day planetary wave with zonal wavenumber 1. The wave amplitudes maximise in winter at middle to high latitudes, where monthly-mean amplitudes can be as large as ~8 K. Significant wave amplitudes are also observed in the summer-time mesosphere and lower thermosphere (MLT) and at lower stratospheric heights of up to ~20 km at middle to high latitudes. Wave amplitudes in the Northern Hemisphere approach values twice as large as those in the Southern Hemisphere. Wave amplitudes are also closely related to mean zonal winds and are largest in regions of strongest eastward flow. There is a reduction in wave amplitudes at the stratopause. No significant wave amplitudes are observed near the equator or in the strongly westward background winds of the atmosphere in summer. This behaviour is interpreted as a consequence of wave/mean-flow interactions. Perturbations in wave amplitude summer MLT are compared to those simultaneously observed in the winter stratosphere of the opposite hemisphere and found to have a correlation coefficient of +0.22, suggesting a small degrees of inter-hemispheric coupling. We interpret this to mean that some of the summer-time MLT wave may originate in the winter stratosphere of the opposite hemisphere and have been ducted across the equator. We do not observe a significant QBO modulation of the 16-day wave amplitude in the polar summer-time MLT. Wave amplitudes were also observed to be suppressed during the major sudden stratospheric warming events of the Northern Hemisphere winters of 2006 and 2009.

 References Alexander, S. P. and Shepherd, M. G.: Planetary wave activity in the polar lower stratosphere, Atmos. Chem. Phys., 10, 707–718, http://dx.doi.org/10.5194/acp-10-707-2010doi:10.5194/acp-10-707-2010, 2010. Baldwin, M., Hirooka, T., O'Neill, T., and Yoden, S.: Major stratospheric warming in the Southern Hemisphere in 2002: Dynamical aspects of the ozone hole split, SPARC Newsletter, 20, 24–26, 2003. Baumgaertner, A. J G., McDonald, A J., Hibbins, R E., Fritts, D C., Murphy, D J., and Vincent, R A.: Short-period planetary waves in the antartic middle atmosphere, J. Atmos. and Solar-Terr. Phys., 70, 1336–1350, 2008. Charney, J G. and Drazin, P G.: Propagation of planetary-scale disturbances from lower into the upper atmosphere, J. Geophys. Res., 66, 83–109, 1961. Chshyolkova, T., Manson, A H., Meek, C E., Avery, S K., Thorsen, D., MacDougall, J W., Hocking, W., Murayama, Y., and Igarashi, K.: Planetary wave coupling processes in the middle atmosphere (30–90km): A study involving MetO and MFR data, J. Atmos. and Solar-Terr. Phys., 68, 353–368, 2006. Day, K. A. and Mitchell, N. J.: The 16-day wave in the Arctic and Antarctic mesosphere and lower thermosphere, Atmos. Chem. Phys., 10, 1461–1472, http://dx.doi.org/10.5194/acp-10-1461-2010doi:10.5194/acp-10-1461-2010, 2010. Espy, P J. and Witt, G.: Observation of a quasi 16-day oscillation in the polar summer mesospheric temperature, Geophys. Res. Letts., 23, 1071–1074, 1996. Espy, P J., Stegman, J., and Witt, G.: Interannual variations of the quasi-16-day oscillation in the polar summer mesospheric temperature, J. Geophys. Res., 102, 1983–1990, 1997. Forbes, J M., Jun, G., and Miyahara, S.: On the interactions between gravity waves and the diurnal propagating tides, Planet. Space Sci., 39, 1249–1257, 1991. Forbes, J M., Hagan, M E., Miyahara, S., Vial, F., Mason, A H., Meek, C E., and Portnyagin, Y I.: Quasi 16-day oscillation in the mesosphere and lower thermosphere, J. Geophys. Res., 100, 9149–9163, 1995. Hibbins, R E., Jarvis, J M., and Ford, E. A K.: Quasi-biennial oscillation influence on long-period planetary waves in the Antarctic upper mesosphere, J. Geophys. Res., 114, DO9109, http://dx.doi.org/10.1029/2008JD011174doi:10.1029/2008JD011174, 2009. Jacobi, C.: The Quasi 16-day Wave in the Summer Midlatitude Mesopause Region and its Dependence on the Equatorial Quasi-Biennial Oscillation, Report of the LIM and the IFT9, Leipzig, 117–129, 1998. Jacobi, C., Schminder, R., and Kürschner, D.: Long-period (12-25 days) oscillations in the summer mesopause region as measured at Collm (52° N, 15° E) and their dependence on the equatorial quasi-biennial oscillation, Atmos. Phys., 1, 461–464, 1998. Jiang, G.-Y., Xiong, J.-G., Wan, W.-X., Ning, B.-Q., Liu, L.-B., Vincent, R A., and Reid, I.: The 16-day waves in the mesosphere and lower thermosphere over Wuhan (30.6° N, 114.5° E) and Adelaide (35° S, 138° E), Advances in Space Research, 35, 2005–2010, 2005. Lima, L M., Batista, P P., Clemasha, B R., and Takahashi, H.: 16-day wave observed in the meteor winds at low latitudes in the southern hemisphere, Advances in Space Research, 38, 2615–2620, 2006. Limpasuvan, V. and Wu, D L.: Anomalous two-day wave behavior during the 2006 austral summer, Geophys. Res. Letts., 36(4), http://dx.doi.org/10.1029/2008GL036387doi:10.1029/2008GL036387, 2009. Limpasuvan, V., Wu, D L., Schartz, M J., Wates, J W., Wu, Q., and Killeen, T L.: The two-day wave in eso mls temperature and wind measurements during 2004–2005 winter, Geophys. Res. Letts., 32(17), http://dx.doi.org/10.1029/2005GL023396doi:10.1029/2005GL023396, 2005. Livesey, N., Filipiak, M., Froidevaux, L., Read, W., Lambert, A., Santee, M., Jiang, J., Pumphrey, H., Waters, J., Cofield, R., Cuddy, D., Daffer, W., Drouin, B., Fuller, R., Jarnot, R., Jiang, Y., Knosp, B., Li, Q., Perun, V., Schwartz, M., Snyder, W., Stek, P., Thurstans, R., Wagner, P., Avery, M., Browell, E., Cammas, J.-P., Christensen, L., Diskin, G., Gao, R.-S., Jost, H.-J., Loewenstein, M., Lopez, J., Nedelec, P., Osterman, G., Sachse, G., and Webster, C.: Validation of Aura Microwave Limb Sounder O<sub>3</sub> and CO observations in the upper troposphere and lower stratosphere, J. Geophys. Res., 113, http://dx.doi.org/10.1029/2007JD008805doi:10.1029/2007JD008805, 2008. Luo, Y., Manson, A H., Meek, C E., Meyer, C K., and Forbes, J M.: The quasi 16-day oscillation in the mesosphere and lower thermosphere at Saskatoon (52° N, 107° W), 1980–1996, J. Geophys. Res., 195, 2125–2138, 2000. Luo, Y., Manson, A H., Meek, C E., Thayaparan, T., MacDougall, J., and Hocking, W K.: The 16-day wave in the mesosphere and the lower thermosphere: simultaneous observations at Saskatoon (52° N, 107° W), London (43° N, 81° W), Canada, J. Atmos. and Solar-Terr. Phys., 64, 1287–1307, 2002a. Luo, Y., Manson, A H., Meek, C E., Meyer, C K., Burrage, M D., Fritts, D C., Hall, C M., Hocking, W K., MacDougall, J., Riggin, D M., and Vincent, R A.: The 16-day planetary waves: multi-MF radar observations from the arctic to equator and comparisions with the HRDI measurements and the GSWM modeling results, Ann. Geophys., 20, 691–709, 2002b. Manson, A H., Meek, C E., Luo, Y., Hocking, W H., MacDougall, J., Riggin, D M., Fritts, D C., and Vincent, R A.: Modulation of gravity waves by planetary waves (2 and 16 d): observations with the North American-Paci􏰌c MLT-MFR radar network, J. Atmos. and Solar-Terr. Phys., 65, 85–104, 2003. Mbatha, N., Sivakumar, V., Malinga, S. B., Bencherif, H., and Pillay, S. R.: Study on the impact of sudden stratosphere warming in the upper mesosphere-lower thermosphere regions using satellite and HF radar measurements, Atmos. Chem. Phys., 10, 3397–3404, http://dx.doi.org/10.5194/acp-10-3397-2010doi:10.5194/acp-10-3397-2010, 2010. McDonald, A J., Hibbins, R E., and Jarvis, J M.: Properties of the quasi-16 day wave derived from EOS MLS observations, J. Geophys. Res., 116(479), D06112, http://dx.doi.org/10.1029/2010JD014719doi:10.1029/2010JD014719, 2011. Merkel, A W., Thomas, G E., Palo, S E., and Bailey, S M.: Observations of the 5-day planetary wave in PMC measurements from the Student Nitric Oxide Explorer Satellite, Geophys. Res. Lett., 30, 1196, http://dx.doi.org/10.1029/2002GL016524doi:10.1029/2002GL016524, 2003. Merkel, A W., Garcia, R R., Bailey, S M., and Russell~III, J M.: Observational studies of planetary waves in PMCs and mesospheric temperature measured by SNOE and SABER, J. Geophys. Res., 113, D14202, http://dx.doi.org/10.1029/2007JD009396doi:10.1029/2007JD009396, 2008. Meyer, C K.: Gravity wave interactions with mesospheric planetary waves: A mechanism for penetration into the thermosphere-ionosphere system, J. Geophys. Res.-Space Phys., 104, 28181–28196, 1999. 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., 17, 1447–1456, 1999. Miyahara, S. and Forbes, M.: Interactions between gravity waves and the diurnal tide in the mesosphere and lower thermosphere, J. Meteorol. Soc. Jpn., 69, 523–531, 1991a. Miyahara, S., Portnyagin, Y I., Forbes, J M., and Solovjeva, T V.: Mean zonal acceleration and heating of the 70- to 100-km region, J. Geophys. Res., 96, 1225–1238, 1991b. Miyoshi, Y.: Numerical simulations of the 5-day and 16-day waves in the mesopause region, Earth Planets Space, 51, 763–772, 1999. Morris, R J., Klekociuk, A R., and Holdsworth, D A.: Low latitude 2-day planetary wave impact on austral polar mesopause temperatures: revealed by a January diminution in PMSE above Davis, Antarctica, Geophys. Res. Letts., 36, L11807, http://dx.doi.org/10.1029/2009GL037817doi:10.1029/2009GL037817, 2009. Nakamura, T., Fritts, D C., Isler, J R., Tsuda, T., Vincent, R A., and Reid, M.: Short-period fluctuations of the diurnal tide observed with low-latitude MF and meteor radars during CADRE: Evidence for gravity wave/tidal interactions, J. Geophys. Res.-Atmos., 102, 26225–26238, 1997. Nielsen, K., Siskind, D E., Eckermann, S D., Hoppel, K W., Coy, L., McCormack, J P., Benze, S., Randall, C E., and Hervig, M E.: Seasonal variation of the quasi 5-day planetary wave: Causes and consequences for polar mesospheric cloud variability in 2007, J. Geophys. Res., 115, D18111, http://dx.doi.org/10.1029/2009JD012676doi:10.1029/2009JD012676, 2010. Salby, M L.: Rossby Normal Modes in Nonuniform Background Configurations. Part I: Simple fields, J. Atmos. Sci., 38, 1803–1826, 1981a. Salby, M L.: Rossby Normal Modes in Nonuniform Background Configurations. Part II: Equinox and Solstice Conditions, J. Atmos. Sci., 38, 1827–1840, 1981b. Schwartz, M J., Lambert, A., Manney, G L., Read, W G., Livesey, N J., Froidevaux, L., Ao, C O., Bernath, P F., Boone, C D., Cofield, R E., Daffer, W H., Drouin, B J., Fetzer, E J., Fuller, R A., Jarnot, R F., Jiang, J H., Jiang, Y B., Knosp, B W., Krüger, K., Li, J.-L F., Mlynczak, M G., Pawson, S., III, J. M R., Santee, M L., Snyder, W V., Stek, P C., Thurstans, R P., Tompkins, A M., Wagner, P A., Walker, K A., Waters, J W., and Wu, D L.: Validation of the Aura Microwave Limb Sounder temperature and geopotential height measurements, J. Geophys. Res., 113, D15S11, http://dx.doi.org/10.1029/2007JD008783doi:10.1029/2007JD008783, 2008. Smith, A K.: Longitudinal variations in mesospheric winds: Evidence for gravity wave filtering by planetary waves, J. Atmos. Sci., 53, 1156–1173, 1996. Smith, A K.: The origins of stationary planetary waves in the upper mesosphere, American Meteorological Society, 3033–3041, 2003. Thayaparan, T., Hocking, W H., and MacDougall, J.: Observational evidence of tidal/gravity wave interactions using the UWO 2 MHz radar, Geophys. Res. Lett., 22, 373–376, 1995. Williams, C R. and Avery, S K.: Analysis of long-period waves using the mesosphere-stratosphere-troposphere radar at poker flats, Alaska, J. Geophys. Res., 97, 20855–20 861, 1992. Wu, D L., Hays, P B., and Skinner, W R.: A least-squares method for spectral-analysis of space-time series, J. Atmos. Sci., 52, 3501–3511, 1995.