HR: 1340h
AN: A33D-0103    [Abstracts]
TI: Improved A Priori for Tropospheric CO Based on Satellite and In-situ Data Analysis
AU: * Deeter, M N
EM: mnd@ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, P. O. Box 3000, Boulder, CO 80307 United States
AU: Edwards, D P
EM: edwards@ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, P. O. Box 3000, Boulder, CO 80307 United States
AU: Emmons, L K
EM: emmons@ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, P. O. Box 3000, Boulder, CO 80307 United States
AU: Gille, J C
EM: gille@ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, P. O. Box 3000, Boulder, CO 80307 United States
AU: Novelli, P C
EM: pnovelli@cmdl.noaa.gov
AF: Climate Monitoring and Diagnostics Laboratory, National Oceanic and Atmospheric Administration, DSRC 2D135 325 Broadway, Boulder, CO 80305 United States
AB: The Measurements of Pollution in the Troposphere (MOPITT) satellite instrument has now produced more than four years of global measurements of tropospheric CO. These data form the basis of a new a priori for tropospheric CO. However, quantitative interpretations of MOPITT retrieved CO profiles must account for the role played by a priori information; current MOPITT retrieved profiles are based on an optimal estimation retrieval algorithm with a fixed (global) a priori profile. Thus, deriving the new a priori directly from the current MOPITT product would necessarily result in regional and seasonal biases. For example, in much of the southern hemisphere, where CO volume mixing ratios are usually much smaller than values in the global a priori profile, MOPITT retrievals are typically positively biased. A revised ``dynamic'' CO a priori without the regional and seasonal biases described above is under development. The key constraint in this development is that, within each a priori domain (defined by some temporal and geographic interval), the average of all profiles retrieved with the new a priori profile is forced to be equal to the new a priori profile for that domain. Principal components analysis applied to in-situ profile datasets from two remote oceanic sites (Hawaii in the northern hemisphere, and Rarotonga in the southern hemisphere) is used to complement the information provided by the MOPITT data. The new seasonally- and latitudinally-variable a priori will be validated using monthly-mean surface station CO measurements compiled by the NOAA Climate Monitoring and Diagnostics Laboratory (CMDL).
DE: 1640 Remote sensing
DE: 0365 Troposphere--composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting