HR: 0800h
AN: A41B-0436    [Abstracts]
TI: Relation Between Backscatter and Depolarization Ratio for ISCCP Cloud Types On the Basis of Collocated MODIS and CALIPSO products
AU: * Cho, H
EM: blueatmos@tamu.edu
AF: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843, United States
AU: Yang, P
EM: pyang@ariel.met.tamu.edu
AF: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843, United States
AU: Kattawar, G
EM: kattawar@physics.tamu.edu
AF: Department of Physics, Texas A&M University, College Station, TX 77843, United States
AU: Hu, Y
EM: yongxiang.hu-1@nasa.gov
AF: National Aeronautics and Space Administration, Langley Research Center, Hampton, VA 23681, United States
AU: Minnis, P
EM: p.minnis@nasa.gov
AF: National Aeronautics and Space Administration, Langley Research Center, Hampton, VA 23681, United States
AU: Winker, D
EM: d.m.winker@larc.nasa.gov
AF: National Aeronautics and Space Administration, Langley Research Center, Hampton, VA 23681, United States
AB: Using the International Satellite Cloud Climatology Project (ISCCP) cloud classification, we investigated the relation of backscatter and backscattering depolarization ratio for nine types of clouds on the basis of the collocated data of the cloud products derived from the measurements made by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Aqua. Specifically, MODIS MYD06 cloud optical thickness and cloud top pressure are used to classify cloud types. For each cloud type, layer-averaged backscatter and backscattering depolarization ratio from the CALIPSO measurements are investigated. High clouds (cirrus, cirrostratus and deeply convective clouds) and mid- and high-latitude altostratus clouds show signatures of both ice and water clouds. We also use MODIS cloud phase flags to screen ice clouds. As a result, the classified high clouds flagged as water clouds show only water phase feature; however, the ice counterparts still show features of both ice and water phases. To understand the depolarization ratio of ice clouds, we also simulated the depolarization ratio for ice crystals using an improved geometric optics model. It is shown that the linear depolarization ratio of ice particles depends on particle habits, which however is not sensitive to effective particle size. Furthermore, we compared the values of the backscattering linear depolarization ratio computed with various habit and size distributions.
DE: 0319 Cloud optics
DE: 0360 Radiation: transmission and scattering
DE: 3360 Remote sensing
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting