A quantitative measure of polar vortex strength using the functionM

摘要: Changes in the dynamics of stratospheric polar vortices can significantly affect composition air stratosphere, with vortex barrier being particularly important. The “Function M” is a recently proposed measure for quantifying transport dynamical systems. We show that it be used not only to visualize structure region detail but also provide basis quantitative measures capturing important aspects dynamics. Two such have been calculated daily August–October 2009 and 2010 Southern Hemisphere potential temperatures 600, 700, 900 K, as well three different Northern winter periods K. discuss strength permeability based on average value function M near edge. second measure, associated area, obtained by calculating area values above threshold. Both are found potentially useful, area-based providing most convincing results. Lagrangian framework follow edge, allowing when retains its integrity identified even greatly distorted. strong linear correlation edge between over time periods, suggesting coherent at least 30 days.