HR: 15:45h
AN: A53A-08    [Abstracts]
TI: Tropospheric Planetary Wave Influence on Polar Stratospheric Clouds Over Davis, Antarctica
AU: * Innis, J L
EM: John.Innis@aad.gov.au
AF: Australian Antarctic Division, 203 Channel Highway, Kingston, Tas 7050, Australia
AU: Klekociuk, A R
EM: Andrew.Klekociuk@aad.gov.au
AF: Australian Antarctic Division, 203 Channel Highway, Kingston, Tas 7050, Australia
AU: Graham, A D
EM: Tony.Graham@aad.gov.au
AF: Australian Antarctic Division, 203 Channel Highway, Kingston, Tas 7050, Australia
AU: French, W J
EM: John.French@aad.gov.au
AF: Australian Antarctic Division, 203 Channel Highway, Kingston, Tas 7050, Australia
AB: Observations of Polar Stratospheric Clouds (PSC) were obtained with a Rayleigh lidar at Davis Station, Antarctica (78.0°~E, 68.6°~S), during the winter of 2006. Davis is located near the nominal edge of the Antartic polar vortex. A strong influence of planetary waves (PW) on the occurrence of PSC was seen, as has been observed for this site in previous seasons. We also saw an apparent correlation between the occurrence of tropopausal cirrus and moderately strong PSC, as has been seen elsewhere by other authors. Examination of the data showed that PW--induced vertical motion was present from low in the troposphere through to at least the mid--stratosphere, resulting in adiabatic cooling (from uplift) and heating (downward motion). The cooling either contributed to the formation of PSC, or allowed previously existing PSC to remain, and possibly intensify. The PW may have a similar influence on the occurrence of tropopausal cirrus. Co--incidental location of cirrus and PSC has been seen previously by others, but in those cases the cause appeared to be uplift resulting from synoptic-- scale disturbances in the upper troposphere, whereas we find that at Davis, during mid--winter, the vertical movement appears to have a planetary--scale origin.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0320 Cloud physics and chemistry
DE: 0350 Pressure, density, and temperature
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly