HR: 15:45h
AN: A34A-01 INVITED     [Abstracts]
TI: Observations of Satellite-Based Temperatures of the Troposphere
AU: * Christy, J R
EM: christy@nsstc.uah.edu
AF: John R. Christy University of Alabama in Huntsville, ESSC/Cramer Hall University of AL in Huntsville, Huntsville, AL 35899
AB: Bulk atmospheric temperatures from microwave sounding units on polar orbiters (MSUs) and their 1998 replacement, the Advanced MSU or AMSU, require significant adjustment before they may be useful for climate analysis. The University of Alabama in Huntsville (UAH) builds their datasets with the emphasis on reducing uncertainties of the long term trends. UAH has a relatively strict requirement that over the life of co-orbiting satellites, both satellites must agree on the trend in the Earth-viewed temperature during the common overlap. Applying this methodology generates calibration adjustments to the various instruments flown on different spacecraft, adjustments that are somewhat different in a few cases than other similar MSU datasets. From Dec 1978 to Dec 2004, the global lower tropospheric trend is estimated at +0.08 ± 0.05 C/decade. Similar results are found in radiosonde-based datasets. Indeed in site-by-site comparisons with over 150 radiosondes in various groupings, the median trend difference was less than ± 0.02 C/decade. Analysis of MSU retrievals based on linearly combining MSU channel 2 and MSU 4 indicate significant instability in that the linear coefficients of MSU2 and MSU4 designed to reproduce a balloon-based tropospheric target temperature vary widely depending upon the dataset used. The result indicates considerable uncertainty in trends when such retrievals are attempted.
DE: 0394 Instruments and techniques
DE: 1610 Atmosphere (0315, 0325)
DE: 1620 Climate dynamics (3309)
DE: 3360 Remote sensing
DE: 3394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly