HR: 0800h
AN: GC21A-0161    [Abstracts]
TI: Warming Asymmetries due to Surface Turbulent Heat Flux Feedbacks in IPCC AR4 Climate Simulations
AU: * Castet, C
EM: ccastet@met.fsu.edu
AF: Department of Meteorology, Florida State University, Tallahassee, FL 32306, United States
AU: Lu, J
EM: jlu@met.fsu.edu
AF: Department of Meteorology, Florida State University, Tallahassee, FL 32306, United States
AU: Cai, M
EM: cai@met.fsu.edu
AF: Department of Meteorology, Florida State University, Tallahassee, FL 32306, United States
AB: We use the newly developed Climate Feedback Response Analysis Model (CFRAM) to evaluate the coupled atmosphere-surface temperature changes due to the surface latent and sensible heat flux feedbacks in IPCC AR4 climate simulations. The CFRAM enables us to examine the warming patterns due to both feedbacks that directly affect the TOA radiative fluxes and feedbacks that do not, such as evaporation and surface sensible flux feedbacks. We estimate the surface flux feedback patterns from the difference between the 2×CO2 and control experiments. The temperature changes attributable to the surface sensible heat flux feedback are positive over the ocean with maximum values over the southern ocean and northern hemisphere gulf currents. Over land, the surface sensible heat flux feedback causes a reduction of surface warming over southern Africa, the northeastern part of South America and around the northern hemisphere mid-latitudes, corresponding to a negative feedback. The temperature response attributable to the evaporation feedback is a warming over land with the exception of the equatorial Africa and the mid to high latitudes of the northern hemisphere. Over oceans, the evaporation feedback is negative, causing a reduction of sea surface warming except over the equatorial Pacific Ocean where the evaporation feedback is positive. Overall, the effects of evaporation and surface sensible flux feedbacks tend to cancel one another. The net temperature change patterns in response to total surface flux feedbacks are positive in the mid-latitudes, Arctic region, and equatorial Pacific, but negative in sub-tropics and over Antarctica.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1630 Impacts of global change (1225)
DE: 1637 Regional climate change
DE: 1694 Instruments and techniques
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting