HR: 1330h
AN: A52B-0783    [PDF]
TI: The Averaging Kernel of CO2 column measurements by the Orbiting Carbon Observatory (OCO), Its Use in Inverse Modeling, and Comparisons to AIRS, SCIAMACHY, and ground-based FTIR
AU: * Connor, B J
EM: b.connor@niwa.co.nz
AF: NIWA, State Highyway 85, Lauder, 9182 New Zealand
AU: Kuang, Z
AF: University of Washington, Dept. of Atmospheric Sciences, Seattle, WA 98195-1640 United States
AU: Toon, G C
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Crisp, D
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Wood, S W
AF: NIWA, State Highyway 85, Lauder, 9182 New Zealand
AU: Barnet, C
AF: NOAA NESDIS/ORA, 5200 Auth Road, Camp Springs, MD 20746 United States
AU: Buchwitz, M
AF: University of Bremen, Institute of Remote Sensing / Environmental Physics, Bremen, D-28334 Germany
AB: The sensitivity of a space-based CO2 measurement varies with height due to the physics of spectroscopy and radiative transfer interacting with atmospheric properties, and to instrument characteristics such as the spectral bandpass, resolution, and noise. Thus it is necessary to take the profile shape and variability with height into account in retrieving the column and in comparing it to other measurements for validation and to inverse models for studies of the CO2 budget. The variation of sensitivity with height is given by the averaging kernel. Errors in the CO2 column due to non-uniform sensitivity are referred to as `smoothing error'. Here we examine the Orbiting Carbon Observatory (OCO) averaging kernel under various assumptions of aerosol optical depth, surface albedo, and solar zenith angle, and show how models can be made to mimic it, thus eliminating smoothing error from source/sink determinations. Next we compare the OCO averaging kernel to those of AIRS, SCIAMACHY, and the ground-based FTIR measurements to be used for validation. Then we assess the ability of the FTIR to copy the altitude sensitivity of the satellite instruments. Finally, we estimate the resulting smoothing error in comparing the measurements to true values and to each other.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere--composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting