HR: 0800h
AN: A41B-0441    [Abstracts]
TI: Investigation of the Radiative Forcings of Thin Cirrus in the Tropical Atmospheres Based on AIRS/ARM Data
AU: * Yue, Q
EM: qingyue@atmos.ucla.edu
AF: University of California, Los Angeles, 405 Hilgard Ave / 7127 Math Sciences Bldg, Los Angeles, CA 90095, United States
AU: Liou, K
EM: knliou@atmos.ucla.edu
AF: University of California, Los Angeles, 405 Hilgard Ave / 7127 Math Sciences Bldg, Los Angeles, CA 90095, United States
AB: We developed a fast thermal infrared radiative transfer model (Yue et al 2007) to retrieve thin cirrus clouds using Atmospheric Infrared Sounder (AIRS) data. The delta-four-stream approximation has been incorporated into our model to account for multiple scattering contributions in the infrared cloudy spectra, important for cirrus with optical depths larger than about 0.3. We apply this improved retrieval method to a number of nighttime thin cirrus scenes in the tropics selected from the AIRS dataset to determine cirrus optical depth and ice crystal size and habit. The Fu-Liou broadband radiative transfer program has been modified to include observed ice particle habits in the parameterization. The solar and infrared radiative forcings and heating rates produced by thin cirrus in the tropical atmosphere have been analyzed using the retrieved cirrus properties along with the new parameterization. Validation of the cirrus retrieval and the computed broadband fluxes has been carried out by comparing them with the ground-based measurements available from the Atmospheric Radiation Measurement (ARM) program. Finally, we will report investigation of the effect of thin cirrus clouds on the radiation budget at the top of atmosphere, at the position of the tropical tropopause, and at the surface.
DE: 3311 Clouds and aerosols
DE: 3359 Radiative processes
DE: 3360 Remote sensing
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting