HR: 0830h
AN: SA41B-0456    [PDF]
TI: Na lidar observed atmospheric instability and OH imager observed ripples as wave breaking signatures
AU: * Li, T
EM: taoli@lamar.colostate.edu
AF: Colorado State University, 200 West Lake Street, Fort Collins, CO 80523 United States
AU: Williams, B P
EM: biffw@lamar.colostate.edu
AF: Colorado State University, 200 West Lake Street, Fort Collins, CO 80523 United States
AU: She, C
EM: joeshe@lamar.colostate.edu
AF: Colorado State University, 200 West Lake Street, Fort Collins, CO 80523 United States
AB: The Platteville OH imager has observed the nighttime all sky images of OH (~87ñ5km) airglow layers since September 2001. On the night of September 5, 2002, we observed small-scale (also called ripple-type) wave structures with horizontal wavelength of 7km and lifetimes of 14.5min. At the same night, the CSU lidar at Fort Collins was in operation, measuring mesopause region temperature, zonal and meridional winds simultaneously. Since the lidar beams in the mesopause region are within the field view of the imager, atmospheric convective and dynamic instability before, during and after the ripples traverse the lidar beam may be assessed. We found that the small-scale wave structures appear at almost the same time with the local instability and they both have similar lifetime scale. This verified that the small-scale wave structures are associated with the localized instability and as suggested in earlier work [Hecht et al., 1997, Fritts et al., 1997], the ripple structure may be taken as signatures of wave breaking. We noted that these small-scale wave fronts are perpendicular to the fronts of much longer-lived gravity waves (30 to 50km horizontal wavelength), and that lidar observed convective instability where ripples occur, as well as dynamic stability in nearby convectively stable regions.
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3384 Waves and tides
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting