HR: 1340h
AN: A43C-1435    [Abstracts]
TI: Aerosol Optical Properties during GoMACCS and CLASIC: Evidence of Cloud Processing and Scavenging
AU: * Nussbaum, N
EM: nussbaum@lanl.gov
AF: Los Alamos National Laboratory, EES, MS D462, Los Alamos, NM 87545, United States
AU: Dubey, M K
EM: dubey@lanl.gov
AF: Los Alamos National Laboratory, EES, MS D462, Los Alamos, NM 87545, United States
AU: Mazzoleni, C
EM: claudio@lanl.gov
AF: Los Alamos National Laboratory, EES, MS D462, Los Alamos, NM 87545, United States
AU: Gramann, J
AF: Los Alamos National Laboratory, EES, MS D462, Los Alamos, NM 87545, United States
AU: Feingold, G
EM: Graham.Feingold@noaa.gov
AF: NOAA ESRL, Chemical Sciences, 325 Broadway, Boulder, CO 80305, United States
AU: Schmidt, S
AF: University of Colorado Boulder, LASP, Duane Smith Building, Boulder, CO 80309-0311, United States
AU: Hubbe, J
AF: Pacific Northwest National Laboratory, P. O. Box 999, Richland, WA 99352, United States
AU: Springston, S
AF: Brookhaven National Laboratory, EE, MS 815E, Upton, NY 11973-5000, United States
AU: Alexander, L
AF: Pacific Northwest National Laboratory, P. O. Box 999, Richland, WA 99352, United States
AU: McCubbin, I
AF: University of Nevada, Dept. of Physics/220, Reno, NV 89557, United States
AU: Arnott, P
AF: University of Nevada, Dept. of Physics/220, Reno, NV 89557, United States
AU: Seinfeld, J
AF: California Institute of Technology, Caltech, 210-41, Pasadena, CA 91125, United States
AU: Berkovitz, C
AF: Pacific Northwest National Laboratory, P. O. Box 999, Richland, WA 99352, United States
AB: Extensive measurements of aerosol absorption and scattering were performed in the Houston area with the Los Alamos photoacoustic instrument (LAPA) during the GoMACCS campaign in the summer of 2006. The LAPA data are combined with other microphysical data to discern the impacts of clouds on aerosols. A statistical analysis reveals that aerosol scattering and absorption decrease with altitude, consistent with the vertical profiles of condensation particle counts. However, the single scattering albedo (ratio of scattering to total extinction) decreases with altitude above the boundary layer when cloud water increases. This indicates that cloud processing could affect the size of distribution and/or the chemical composition of the aerosols. On particular days we observed long range polluted air at high altitude, which gradually subsided and could be discriminated from the local boundary layer pollution. We examine a variety of correlations between aerosol and cloud properties that would be useful in elucidating the indirect effect. We also analyze the impact of shallow convective cloud fields on aerosol optical properties, both above and below cloud. Finally we report aerosol optical measurements collected in Oklahoma during the CHAPS campaign in the summer of 2007. We apply a similar statistical methodology to differentiate between cloud and clear air observations and report preliminary findings. We detected polluted air masses where both CO and scattering were enhanced in cloud-free air. However, in cloudy air the aerosol scattering was reduced, probably due to scavenging. These results will help us quantify the effects of clouds on aerosols in polluted air masses in the outflow of urban areas.
UR: http://aerosols.lanl.gov
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0319 Cloud optics
DE: 0320 Cloud physics and chemistry
DE: 0321 Cloud/radiation interaction
DE: 0360 Radiation: transmission and scattering
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting