HR: 0800h
AN: A31A-0820    [Abstracts]
TI: An Examination of Spatial Scaling Effects on the Construction of Vertical Profiles of Aerosol Concentrations and Particle Size Distributions for Use in the Validation of Remotely-Sensed Aerosol Estimates
AU: * Richardson, D L
EM: dlr2n@virginia.edu
AF: Department of Environmental Sciences, University of Virginia, 291 McCormick Rd. POB 400123, Charlottesville, VA 22904 United States
AU: Swap, R J
EM: rjs8g@virginia.edu
AF: Department of Environmental Sciences, University of Virginia, 291 McCormick Rd. POB 400123, Charlottesville, VA 22904 United States
AU: Stein-Zweers, D C
EM: dcs5v@virginia.edu
AF: Department of Environmental Sciences, University of Virginia, 291 McCormick Rd. POB 400123, Charlottesville, VA 22904 United States
AU: Piketh, S J
EM: stuart@wits.bpb.ac.za
AF: Climatology Research Group, University of the Witwatersrand, WITS, Johannesburg, 2050 South Africa
AB: To investigate the role of the internal vertical structure and the relative contribution to columnar optical thickness by aerosol layers upon remotely-sensed aerosol products, it is important to validate these products using in situ data in addition to other optical full-column aerosol measurements from ground, plane, and space-based platforms. However, constructing vertical profiles of aerosol concentration and particle size distribution from in situ data presents special temporal and spatial scale-related problems due to a number of factors including: 1.) the movement of the air parcels that make up the vertical profile by winds during the collection period when taking into account the time differential between in situ collection and satellite overpass; and 2.) the lateral spatial extent necessary for the in situ aircraft to cover for it to be able to ascend or descend through the full vertical profile. Using in situ data collected over southern Africa as part of the SAFARI-2000 dry season field campaign, we examined the potential differences in resulting aerosol concentrations and particle size distributions between a traditional ``full flown profile" approach using the flight segment as the basic unit of observation and a more spatially-limited pixel-based approach that involved interpolation and extrapolation of the in situ data in order to construct each pixel-specific profile. We found that the resulting vertical profiles and aggregated pixel aerosol indices were similar for both approaches in those cases where the vertical profiles could be built from intentional spiral flight paths over fixed locations, but important differences result when constructing vertical profiles for those flight legs that cover a large linear distance while alternately ascending and descending in altitude, a pattern sometimes known as ``porpoising". These differences became less pronounced as the resolution of the remotely-sensed data became coarser, such as when comparing the in situ data to TOMS rather than MODIS satellite data.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005