HR: 17:30h
AN: SA24A-07    [Abstracts]
TI: An earlier lidar observation of a noctilucent cloud above Logan, Utah Center for Atmospheric and Space Sciences, Utah State University
AU: * Herron, J P
EM: joshua.herron@usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences, 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Wickwar, V B
EM: vincent.wickwar@usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences, 4405 Old Main Hill, Logan, UT 84322-4405 United States
AB: The Atmospheric Lidar Observatory (ALO) Rayleigh-scatter lidar has been operated for 11 years on the Utah State University (USU) campus (41.7$\deg$ N 111.8$\deg$ W). During the morning of 22 June 1995 a noctilucent cloud (NLC) was observed with the lidar, well away from the twilight periods when NLCs are visible. It lasted for approximately one hour. The temperature profiles, calculated at hourly intervals, were at least 20 K cooler than the 11-year June climatological average for ALO near the NLC altitude. These cool temperatures arose, in part, because of a major temperature oscillation. This NLC observation at ALO and a previously reported one from 1999 [{\it Wickwar et al.,} 2002] are very significant because they show the penetration of NLCs equatorward of 50$\deg$, which may have important implications for global change.
DE: 3360 Remote sensing
DE: 3384 Waves and tides
DE: 1610 Atmosphere (0315, 0325)
DE: 0340 Middle atmosphere--composition and chemistry
DE: 0350 Pressure, density, and temperature
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting