HR: 1340h
AN: A43B-0084    [Abstracts]
TI: Direct Retrieval of Radiative Flux-Divergence and Radiative Forcing from Satellite Spectral Measurements.
AU: * Feldman, D
EM: feldman@caltech.edu
AF: California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Liou, K
EM: knliou@atmos.ucla.edu
AF: University of California, Los Angeles, 405 Hilgard Ave Box 951565 7127 Math Sciences Bldg., Los Angeles, CA 90095 United States
AU: Yung, Y
EM: yly@gps.caltech.edu
AF: California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Tobin, D
EM: dave.tobin@ssec.wisc.edu
AF: University of Wisconsin, Madison, 1225 W. Dayton St., Madison, WI 53706 United States
AU: Berk, L
EM: lex@spectral.com
AF: Spectral Sciences, Inc., 4 Fourth Ave., Burlington, MA 01803 United States
AB: We explore the concept of a retrieval of the thermal infrared radiative flux divergence and cooling rate profile using top-of-atmosphere spectral radiance measurements and demonstrate that the retrieval of this quantity can be performed directly. We show that the inversion encountered in this problem is sensitive to the initial atmospheric state vector assumed a priori. However, the direct approach has specific advantageous in terms of accuracy and computational speed, as compared to the conventional indirect approach using the retrieved atmospheric state vector coupled with a line-by-line radiative transfer model in cooling rate calculations. Furthermore, we show that the spectrally-resolved radiative forcing at the tropopause can be derived directly from the retrieved flux-divergence profile. As a test case, we carried out retrieval in the strong cooling band associated with the 15 μm band of CO₂ employing the Atmospheric Infrared Sounder (AIRS, 2002-present) on board the Aqua satellite, along with validation campaign data and underflight Scanning High-Resolution Interferometer (S-HIS) zenith and nadir spectra taken aboard a high-altitude aircraft. Retrieval sensitivity analyses have been performed for AIRS and the Infrared Interferometer Sounder (IRIS-D, 1970-1971) instruments. It is anticipated that the large changes in stratospheric temperature and CO₂ values between the two missions would lead to detectable changes in the CO₂ radiative forcing at the tropopause so long as the IRIS-D instrument could be appropriately characterized.
UR: http://www.gps.caltech.edu/~drf/misc/agu2005/
DE: 0360 Radiation: transmission and scattering
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005