HR: 11:30h
AN: A22B-07 INVITED    [Abstracts]
TI: A parameter study of climate using an idealized GCM
AU: * Lee, S
EM: sl@meteo.psu.edu
AF: Department of Meteorology, The Pennsylvania State University, 503 Walker Building, University Park, PA 16802, United States
AU: Son, S
EM: sws2112@columbia.edu
AF: Department of Applied Physics and Applied Mathematics, Columbia University, 200 S. W. Mudd Building, 500 W. 120th St., New York, NY 10027, United States
AB: The results from a series of idealized climate model runs are reviewed. For these model runs, two parameters were varied, one parameter that determines the strength of the tropical heating (H), and the other parameter that determines the width of the baroclinically unstable region (C). By varying these parameters over a range of earth-like parameter settings and then by comparing the results for different parameter values, we gain deeper insight into basic dynamical properties of the atmosphere than by analyzing individual model runs in isolation. It is found that the properties of the climatological zonal flow are closely tied to the properties of the variability of the zonal flow. For the weak C and strong H regime, it is found that the climatolological jet is comprised of a single eddy-driven jet, whereas for the strong C and weak H regime, the climatological jet is characterized by the presence of two jets, a subtropical jet and an eddy driven jet. For the former regime, it is found that the zonal index (latitudinal jet meanders) dominate, whereas for the latter regime the primary form of variability is that of poleward propagating zonal mean flow anomalies. The above results suggest that both the time-mean and the temporal variability of the zonal mean flow may be determined by two key parameters of the heating field. These results in turn allow us to examine other dynamical questions, such as what dynamical processes drive the poleward zonal mean anomaly propagation, what determines the time scale of the zonal index or annular mode, and what propertiess of the flow are essential for determining whether the flow is predictable.
DE: 1620 Climate dynamics (0429, 3309)
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3362 Stratosphere/troposphere interactions
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting