Journal of Atmospheric and Solar-Terrestrial Physics 68 (2006) 901–910 Rayleigh lidar observations of planetary waves in the middle atmosphere over Gadanki (13.51N, 79.21E) P. Kishore a,Ã , S.P. Namboothiri a , K. Igarashi a , V. Sivakumar b , S. Thulasiraman c , I.V. Subba Reddy d , K. Mizutani a , D. Narayana Rao e , S.V.B. Rao d , Y. Bhavani Kumar e a National Institute of Information and Communications Technology, Tokyo, Japan b Laboratoire de Physique de l’Atmosphere, Universite de La Reunion, France c Centre for Atmospheric Research Experiments Meteorological Services of Canada, Ont., Canada d Department of Physics, Sri Venkateswara University, Tirupati, India e National MST Radar Facility, Dept. of Space, Gadanki, Tirupati, India Received 12 May 2005; received in revised form 29 December 2005; accepted 17 January 2006 Available online 23 March 2006 Abstract Rayleigh lidar temperature data collected at Gadanki (13.51N, 79.21E) during two campaign periods in 1999 and 2000 have been analyzed to study the planetary wave activities in the stratosphere and lower mesosphere. Attention has been given to the Rossby-gravity (RG) wave, fast Kelvin wave, and slow Kelvin wave with remarkable periodicity of 3.6, 6.5, and 16 days, respectively. The well-known Lomb–Scargle periodogram (L–S) analysis was performed on the temperature profile to extract the wave characteristics. The analysis indicated the dominance of these waves in the stratosphere and mesosphere. The results obtained are consistent with other measurements based on radar, rocketsonde or satellite. r 2006 Elsevier Ltd. All rights reserved. Keywords: Rayleigh lidar; Middle atmosphere; Planetary wave; Tropical meteorology 1. Introduction Monitoring of the middle-atmospheric tempera- ture has received much attention by the scientific community, due to the value of studies of the chemical reactions and the need to characterize wave dynamics (gravity waves, tides and planetary waves) and their interactions (Singh et al., 1996). There have been a number of techniques involving space-borne and ground-based instruments for middle atmospheric temperature measurements. Among those, the Rayleigh lidar, providing con- tinuous measurements of temperature (or density) with high time and height resolutions over a height range of 30–80 km, has emerged as the most potent ground-based technique to study the structure and dynamics of the middle atmosphere (e.g., Hauche- corne and Chanin, 1980, 1982, 1983; Chanin and Hauchecorne, 1981, 1991; Chanin, 1989; Whiteway and Carswell, 1994; LeBlanc et al., 1998; Sivakumar et al., 2003). Atmospheric temperatures measured by lidars have been used to validate various satellite ARTICLE IN PRESS www.elsevier.com/locate/jastp 1364-6826/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.jastp.2006.01.010 Ã Corresponding author. Tel.: +81 42 327 5463; fax: +81 42 327 5321. E-mail address: kishore@nict.go.jp (P. Kishore).