9528471 Plumb This project represents an ongoing collaboration between Drs. Alan Plumb of MIT (under this award) and Dr. Lorenzo Polvani of Columbia University (ATM-9527315) concerning the dynamics of nonlinear atmospheric waves and vortices, with particular emphasis on applications to the stratosphere. In this work, a number of tools have been employed. Initially, the techniques of contour dynamics was used to study, at very high resolution, the characteristics of Rossby wave breaking under a variety of circumstances. The principal investigators then used a global, pseudospectral, shallow water model to look at the two-dimensional dynamics of nonlinear waves in the presence of nonconservative processes as well as a "contour advection" technique (a Lagrangian, high resolution, contour-following approach to depict transport in known flows. To extend these results, the PIs will examine the three-dimensional aspects of the interaction between Rossby waves and the stratospheric polar vortex using a multi-layer, pseudospectral, primitive equation model. They also will investigate various aspects of the tropospheric circulation related to Rossby wave dynamics - including atmospheric blocking and interactions between the Hadley circulation and midlatitude planetary waves. ***
