TUESDAY, February 20, 2007
Time: 1:40 PM
ECS 1202

Title: Basic Mechanisms for Jet-Stream Horizontal Shear-Induced High-Altitude Turbulence

Iordanka Panayotova

High-altitude clear air turbulence (CAT) forecasting is a problem of great interest for the commercial and general aviation as it is a major reason for over 40 percent of all weather-related aircraft accident and incident reports. Current turbulence forecasts have in general shown poor performance. This is due in part to the fact that turbulence in the atmosphere is a result of a variety of ill-understood, complex and non-linear processes. Two-thirds of severe CAT occurs in the regions around the jet streams where the horizontal shear prevails. In this connection my work is aimed at providing a basic understanding of the mechanisms leading to CAT in those regions by applying idealized mathematical models. In my talk I will focus on a three-dimensional mathematical model describing the incompressible, inviscid and stratified medium with horizontally varying mean flow. Some results that extend the classical hydrodynamic stability theory to three-dimensional disturbances in this model will be presented. I will also discuss a method for solving the linearized system of governing equations for the whole class of basic wind profiles. To study the non-linear wave-mean flow interactions I employ the multiple scale perturbation expansions and obtain the wave amplitude non-linear Schrodinger-like equation. Finally, I will address some directions for my future research.