HR: 1340h
AN: A43D-0135    [Abstracts]
TI: Developing a Nighttime Cirrus Climatology Using AIRS Data and Understanding its Errors and Variability
AU: * Kahn, B H
EM: brian.h.kahn@jpl.nasa.gov
AF: Jet Propulsion laboratory, 4800 Oak Grove Drive MS 169-237, Pasadena, CA 91109-8099 United States
AU: Liou, K
EM: knliou@atmos.ucla.edu
AF: University of California at Los Angeles, 405 Hilgard Avenue Box 951565, Los Angeles, CA 90095-1565 United States
AU: Eldering, A
EM: annmarie.eldering@jpl.nasa.gov
AF: Jet Propulsion laboratory, 4800 Oak Grove Drive MS 169-237, Pasadena, CA 91109-8099 United States
AB: We present a climatology of cirrus clouds at nighttime obtained from the Atmospheric Infrared Sounder (AIRS), located onboard the NASA EOS-Aqua platform, over the subtropical and tropical oceanic regions. With the successful launch of AIRS in May 2002, over three years of nearly continuous and global high-spectral-resolution infrared observations of clouds have been obtained. In this paper, we use a method of cirrus cloud detection that utilizes a combination of brightness temperature differences from IR window channels, total column precipitable water vapor, and operational retrievals of cloud top pressure. Monthly and seasonal maps of cirrus are presented, and some major spatial and temporal patterns of cirrus variability are highlighted. In particular, we will address the detection of thin cirrus clouds in and around the tropical Pacific warm pool region. Another emphasis of this paper is on understanding the validity of the assumptions employed to represent some of the physical quantities in the cirrus detection methodology, including surface emissivity and skin-air temperature differences, and construct reasonable error bounds for these quantities based on available observations and existing theory. This provides a means for relating the error bounds of particular physical quantities to cirrus cloud coverage and amount and, hence, cirrus cloud trends.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0360 Radiation: transmission and scattering
DE: 1640 Remote sensing (1855)
DE: 3311 Clouds and aerosols
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005