HR: 17:00h
AN: A52G-05    [PDF]
TI: Multi-year Characterization of PSCs Using Solar Occultation Satellite Observations
AU: * Strawa, A W
EM: astrawa@mail.arc.nasa.gov
AF: NASA Ames Research Center, M/S 245-4, Moffett Field, CA 94035 United States
AU: Drdla, K
EM: katja@katja.arc.nasa.gov
AF: NASA Ames Research Center, M/S 245-4, Moffett Field, CA 94035 United States
AU: Bokarius, K
EM: kostya@aerosol.arc.nasa.gov
AF: NASA Ames Research Center, M/S 245-4, Moffett Field, CA 94035 United States
AU: Fromm, M
EM: mike.fromm@nrl.navy.mil
AF: Computational Physics, Inc.,, Code 7227 4555 Overlook Ave., SW, Washington, DC 20375 United States
AU: Alfred, J
EM: jerome.alfred@nrl.navy.mil
AF: Computational Physics, Inc.,, Code 7227 4555 Overlook Ave., SW, Washington, DC 20375 United States
AB: POAM solar occultation observations from1994 to present are studied for the purpose of determining Type I PSC formation characteristics and winter-long evolution. This information is critical to an improved understanding and predictive capability of stratospheric ozone depletion. Solar occultation satellite observations of these clouds yields more continuous and wide-spread information than can be obtained from aircraft, balloon, or ground-based observations. This multi-winter PSC study is augmented by the use of our Type Ia/Ib discrimination scheme. Recent studies of PSC formation made with POAM observations and simulations during the 1999-2000 Arctic winter have shown characteristics that shed light on the formation mechanisms responsible for Type Ia solid phase PSCs. This study examines PSC observations from many years on a common basis to see if the characteristics observed during the 1999-2000 Arctic winter are observed in other years and if other characteristics can be identified. The results show that Type Ia PSCs form at the beginning of the winter, within several days of the first drop in temperature below NAT frost point, and peak early in the winter. Type Ia PSCs typically outnumber Ib PSCs over the winter, especially at the beginning of the winter. Type Ia and Ib PSC observations continue throughout the winter. Micro-physical models of PSC formation must match these observed characteristics. Differences in PSC characteristics between the first two Arctic winters (1994-1995 and 1995-1996) and later winters also suggest the influence of volcanic perturbations on PSC formation. Type Ia and Ib PSC characteristics observed by POAM III and SAGE III for the 2002-2003 Arctic winter are compared.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0340 Middle atmosphere--composition and chemistry
DE: 0370 Volcanic effects (8409)
DE: 1610 Atmosphere (0315, 0325)
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting