This award is one of two separate awards being made for a collaborative project between Dr. Lorenzo Polvani of Columbia University and Dr. Alan Plumb of MIT (ATM-9218841). Their research involves the simulation and understanding of nonlinear aspects of large-scale wave and eddy motions in the atmosphere, using the technique of contour dynamics with surgery (CD/S). This is an efficient computational procedure for the investigation at high resolution of processes such as the spectral cascade of enstrophy in highly nonlinear flows. The PIs plan to apply this technique to investigate further the dynamics of the stratospheric polar vortex, the interaction of quasi-stationary long waves and the Rossby wave dispersion relation in situations where the potential vorticity gradient is concentrated rather than continuous from pole to pole. In addition, they have developed a technique of contour advection with surgery (CA/S) in which the numerical procedures of the CD/S approach have been used to develop a sophisticated trajectory code. This is a diagnostic method which can reveal much about the distortion and buckling of material surfaces in observed flows, and it will be applied to investigate such effects in the stratosphere and in the upper troposphere.
