HR: 16:30h
AN: SA34A-03    [Abstracts]
TI: The Climatology of the 5-Day Wave in the Mesosphere
AU: * Riggin, D M
EM: riggin@colorado-research.com
AF: Colorado Research Assoc. Div. NorthWest Research Associates, 3380 Mitchell Lane, Boulder, CO 80301 United States
AU: Lieberman, R S
AF: Colorado Research Assoc. Div. NorthWest Research Associates, 3380 Mitchell Lane, Boulder, CO 80301 United States
AU: Liu, H
EM: liuh@ucar.edu
AF: High Altitude Observatory NCAR, 3450 Mitchell Lane, Boulder, CO 80301 United States
AB: In the upper mesosphere, westward propagating waves are sometimes observed with periods between 5 and 7 days. These motions are usually attributed to the so-called 5-day wave, a wavenumber 1, Rossby planetary wave that has been extensively studied in the stratosphere. A survey was carried out of planetary wave signatures in SABER temperatures over the three years of the mission. We find that 5-day wave events are relatively infrequent in the upper mesosphere. However, during May of 2003, an exceptionally strong outbreak of 5-day wave activity was observed by SABER with an amplitude of 15 K at mesopause heights. The wave penetrated well into the thermosphere. Although the period of this wave was longer than 5 days ($\sim$6 days), its global structure was consistent with that of the 5-day normal mode. The May 2003 event also showed up strongly in a year-long run of the NCAR TIME-GCM model that was forced at the 10 hPa lower boundary with NCEP reanalyses. The model output is used to study the relationship of mesospheric 5-day wave activity to perturbations in the lower atmosphere and diagnose the background conditions that determine wave propagation and amplification.
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3337 Numerical modeling and data assimilation
DE: 3360 Remote sensing
DE: 3384 Waves and tides
DE: 3309 Climatology (1620)
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting