9712834 Feldstein This award provides renewed support for continued investigations into the nature of zonal-mean flow variability, regional low-frequency variability, and multiple zonal jet dynamics. In their studies, the principal investigators will employ a hierarchy of models, ranging from simple barotropic to multi-level primitive equation, as well as the NCEP/NCAR reanalysis data sets. This combined approach of idealized models and observational data is likely to provide important insights into the dynamical processes they seek to understand. Among the questions that will be explored are: the role of the barotropic processes in the suppression of eddy feedback for the zonal index (the zonal index being represented by the latitudinal displacement of the jet maximum), whether the prominent regional low-frequency anomalies are dominated by linear processes, the source for low-frequency variability of atmospheric flows, and whether stochastic processes are responsible for the inter-jet disturbances in cases of multiple-jet flows. While of considerable theoretical interest, this research ultimately will have practical application in the improvement of extended range forecasting.
