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Science Lecture by Mark Olsen |
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Date: June 19, 2007
Time: 10:30am
Location: NIA, Rm 137
Additional Information: Presentation (.pdf)
Stratosphere-Troposphere Exchange: Why, Where, and How Much?
Mark Olsen, University of Maryland, Baltimore County
and NASA Goddard Earth Sciences and Technology Center
This presentation will begin with a basic overview of stratosphere-troposphere exchange (STE) and outline our present understanding of the STE of both mass and ozone. Several methods of diagnosing STE from models and measurements will be discussed and compared. Results from two current studies will be presented that illustrate the importance of STE on the troposphere and how STE is linked to the dynamics in the troposphere and stratosphere. In one study, ozone data from instruments on the Aura satellite platform are used to determine daily high-resolution tropospheric ozone and extratropical ozone STE. Comparison of the tropospheric ozone maps with the location and magnitude of STE indicates that a significant fraction of tropospheric ozone maxima are influenced by STE. In the second study, a general circulation model is driven with observed sea surface temperatures. The simulation exhibits an increasing trend in the mass STE as a result of changes to the dynamic forcing of the stratosphere. Thus, STE is a useful marker of changes to the stratospheric residual circulation.
Dr. Mark Olsen is a research scientist with the Goddard Earth Sciences and Technology Center (GEST) of the University of Maryland, Baltimore County located at NASA Goddard Space Flight Center. He received a Ph.D. from the Department of Physics and Astronomy at Iowa State University and a B.S. in physics from the University of Northern Iowa. His research interests include upper-troposphere/lower-stratosphere interactions and transport on both global and fine scales, and atmospheric constituent trends and the relationship to climate and climate change.
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