Debra Wicks Kollonige, W. Wallace McMillan, Lynn Sparling, Department of Physics, and Susan Strahan, GEST

In order to accurately predict trends in atmospheric composition, some of the processes requiring a more thorough understanding include the dynamical, chemical, and radiative coupling of the stratosphere and troposphere. Particularly significant is the transport or exchange of trace gases, both natural and anthropogenic, between the stratosphere and troposphere also known as stratosphere-troposphere exchange (STE). In this project, we study observations from NASA's A-Train satellites to determine the global frequency, distribution, and spatial extent of reversible and irreversible mixing of chemical species due to STE. Our initial analyses focus on STE events during NASA's Intercontinental Chemical Transport Experiment - Phase B (INTEX-B) in April and May 2006 over the western North Pacific and United States. The Atmospheric InfraRed Sounder (AIRS) onboard the Aqua satellite provides wide horizontal coverage and vertical profiles of ozone, water vapor, carbon monoxide, and temperature that capture STE events associated with the jet stream. The Tropospheric Emission Sounder (TES) onboard the Aura satellite yields higher vertical resolution of the same atmospheric tracers, but in a narrow sub-satellite swath. The HIgh Resolution Dynamics Limb Sounder (HIRDLS), also on Aura, can show the finer details of mixing associated with STE events. Together, A-Train observations provide a more complete three-dimensional view of STE events than previously possible. In this work, we also utilize additional measurements from meteorological data and aircraft to build a complete view of STE events. Chemical and dynamical analyses, including tracer-tracer correlations, potential vorticity gradients, and trace gas gradients, are used to identify the spatial and temporal distribution of STE events. We intend to run trajectories to view the evolution of these fields in a Lagrangian frame. Finally, we will compare our satellite analyses to the Global Modeling Initiative (GMI) combined chemistry model to evaluate their abilities to accurately quantify STE regionally and then globally over at least one year of A-Train observations.