HR: 0800h
AN: SA21A-0334    [Abstracts]
TI: Vertical structure of NLCs observed by Odin/OSIRIS
AU: * von Savigny, C
EM: csavigny@iup.physik.uni-bremen.de
AF: Institute of Environmental Physics and Remote Sensing, University of Bremen Otto-Hahn-Allee 1, Bremen, 28334 Germany
AU: Petelina, S V
EM: svetlana@osirus.usask.ca
AF: ISAS, Department of Physics and Physics Engineering, University of Saskatchewan 116 Science Place, Saskatoon, SK S7N 5E2 Canada
AU: Llewellyn, E J
EM: edward.llewellyn@usask.ca
AF: ISAS, Department of Physics and Physics Engineering, University of Saskatchewan 116 Science Place, Saskatoon, SK S7N 5E2 Canada
AU: Burrows, J P
EM: burrows@iup.physik.uni-bremen.de
AF: Institute of Environmental Physics and Remote Sensing, University of Bremen Otto-Hahn-Allee 1, Bremen, 28334 Germany
AU: Degenstein, D A
EM: doug.degenstein@usask.ca
AF: ISAS, Department of Physics and Physics Engineering, University of Saskatchewan 116 Science Place, Saskatoon, SK S7N 5E2 Canada
AU: Lloyd, N D
EM: nick.lloyd@usask.ca
AF: ISAS, Department of Physics and Physics Engineering, University of Saskatchewan 116 Science Place, Saskatoon, SK S7N 5E2 Canada
AB: The vertical variation of NLC particle sizes is investigated with limb scattering observations in the UV-B spectral range performed with the Optical Spectrograph and InfraRed Imager System (OSIRIS) on the Odin satellite. The particle sizes are determined under the assumptions that NLC particles can be treated as Mie-scatterers with known refractive index, and that their size distribution can be approximated by a log-normal distribution. OSIRIS is particularly suited to resolve vertical NLC structure due to its narrow vertical field of view of about 1 km. A sample data set of several dozen bright NLCs detected on different days during the 2003 NLC season in the northern hemisphere and the 2003/2004 NLC season in the southern hemisphere was selected for this study. In almost all the cases the derived NLC particle size increases with decreasing altitude. This confirms the standard picture of larger particles at the bottom of the cloud due to sedimentation. The derived particle mode radii estimates fall within the range from about 20 to 60 nm assuming a width parameter of $\sigma=1.4$ for the log-normal distribution.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0394 Instruments and techniques
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting