HR: 0800h
AN: A31B-0312    [Abstracts]
TI: Constraining Climate Sensitivity Using SI Traceable Satellite Data
AU: * Dykema, J A
EM: dykema@fas.harvard.edu
AF: Harvard University, School of Engineering and Applied Sciences, 12 Oxford Street, Cambridge, MA 02138, United States
AU: Leroy, S S
EM: leroy@huarp.harvard.edu
AF: Harvard University, School of Engineering and Applied Sciences, 12 Oxford Street, Cambridge, MA 02138, United States
AU: Anderson, J G
AF: Harvard University, School of Engineering and Applied Sciences, 12 Oxford Street, Cambridge, MA 02138, United States
AB: Profiles of microwave refractivity obtained by radio occultation using the Global Navigation Satellite System (GNSS) provide a benchmark of climate that is on-orbit traceable to the international definition of the second. We have shown that profiles of microwave refractivity provide a high signal-to-noise ratio measurement of the poleward expansion of the Hadley circulation, a sensitive measure of climate change. This measure of Hadley expansion is obtained through the application of standard methods of fingerprinting. By accounting for the uncertainty in the fingerprint of future climate change, these standard fingerprinting methods may be transformed to provide a powerful means of detecting regional climate change, especially those changes pertaining to bulk atmospheric structure and surface air temperature. In this presentation, we examine the prospect of constraining the transient sensitivity of the climate system with timeseries of GNSS occultation. It is expected that a timeseries of GNSS occultation will serve to estimate the response of the climate to forcing, but timeseries of spectrally resolved infrared radiance will also be necessary to estimate the radiative forcing by anthropogenic greenhouse gases. Together, the transient sensitivity of the climate can be observationally determined. The multi-model ensemble of the Coupled Model Intercomparison Project phase 3 (CMIP3) provides a convenient ensemble of opportunity to evaluate the certainty of the physics that relates trends in atmospheric microwave refractivity to trends in surface air temperature. The physical relationship is strong, and hence the utilization of the refractivity profiles provides a strong suppression of natural variability that decreases the amount of time necessary to estimate the transient sensitivity of the climate. We explore the application of this method to the combined timeseries obtained from the CHAMP and COSMIC missions.
DE: 0360 Radiation: transmission and scattering
DE: 0394 Instruments and techniques
DE: 1626 Global climate models (3337, 4928)
DE: 1694 Instruments and techniques
DE: 1855 Remote sensing (1640)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting