Observed 3D to 2D energy cascade in hurricanes

Improved understanding of turbulent processes in the hurricane boundary has been identified as one of the key steps to improve the forecast capability of models. Predicting the intensity of a tropical cyclone, and in particular, those that undergo rapid intensification, is a difficult problem and depends upon the available energy sources from which the hurricane can draw upon. A fundamental question is where does the energy comes from and where does it go. Here we present two important results based on in-situ aircraft data: The first measurement of a 2D inverse cascade in an atmospheric flow and the 3D to 2D turbulence transition in the hurricane boundary layer. Such a transition fundamentally changes the underlying energy dynamics of the flow, such that energy flows from small to large scales in 2D and large to small in 3D.