HR: 1340h
AN: A43C-1437    [Abstracts]
TI: EFFECTS OF AEROSOLS ON TRADE WIND CUMULI OVER THE GULF OF MEXICO: A MODELING AND OBSERVATIONAL STUDY
AU: * Yang, H
EM: hyang31@atmos.uiuc.edu
AF: Department of Atmospheric Sciences, University of Illinois, 105 S.Gregory st., Urbana, IL 61802, United States
AU: McFarquhar, G M
EM: mcfarq@atmos.uiuc.edu
AF: Department of Atmospheric Sciences, University of Illinois, 105 S.Gregory st., Urbana, IL 61802, United States
AU: Wang, H
EM: Hailong.Wang@noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences (CIRES), NOAA, 325 Broadway, R/CSD3, Boulder, CO 80305, United States
AU: Hostetler, C A
EM: Chris.A.Hostetler@nasa.gov
AF: NASA Langley Research Center, National Aeronautics and Space Administration Langley Research Center, Hampton, VA 23681, United States
AU: Ferrare, R A
EM: Richard.A.Ferrare@nasa.gov
AF: NASA Langley Research Center, National Aeronautics and Space Administration Langley Research Center, Hampton, VA 23681, United States
AB: The three-dimensional non-hydrostatic Eulerian and semi-Lagrangian (EULAG) anelastic model with warm-rain bulk microphysics was used to investigate how the distribution and physical properties of aerosols affect radiative forcing directly and indirectly over the Gulf of Mexico. Simulations over a 6.4 km by 6.4 km by 3 km domain were initialized with soundings and sea surface temperatures measured on board the Ron Brown research vessel, and with aerosol optical properties retrieved from the High Spectral Resolution Lidar (HSRL) during the Gulf of Mexico Atmospheric Composition and Climate Study(GoMACCS). The vertical profiles of aerosol extinction retrieved from HSRL and Twin Otter flights showed that a Saharan dust layer consisting of non-absorbing aerosols such as ammonium sulfate, dust, seasalt, and nitrate, was overlaid above the cloud layer for several event days. The impact of the Saharan dust layer on cumuli properties was investigated through a series of tests that simulated the diurnal cycle of the cloud field including and excluding the presence of dust on a number of different days. Preliminary results for the 28 August case study show that the dust layer had little impact on the cumuli evolution through its effect on the radiative heating profile. Additional cases will be simulated and presented at the meeting, together with an evaluation of the model results using in-situ and remote sensing data acquired on different days in a variety of meteorological conditions. Comparison will also be made against simulations conducted over the Indian Ocean to further determine how variations in meteorological conditions impact aerosol indirect forcing.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0320 Cloud physics and chemistry
DE: 0321 Cloud/radiation interaction
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting