This talk is presented in-person and as a Zoom Webinar and requires a passcode. For anyone outside the department; If you would like to attend, email Lan Lewis, [email protected].

 Abstract: 

The coupling between the troposphere and stratosphere is an important component of the global general circulation of the atmosphere. It also plays an important role in understanding the global budget of chemical constituents and their feedback on the climate system. In this talk, I will focus on the two-way stratosphere-troposphere coupling and transport during Northern Hemisphere summer, First, I will show that there is a fast transport pathway that connects the Northern Hemisphere surface to the upper troposphere and lower stratosphere and it occurs over the southern slope of the Tibetan Plateau and northern India with a modal time scale of 5-10 days. A detailed budget analysis reveals that, while convective processes are responsible for transport to 200-300 hPa, the resolved dynamics, specifically the vertical flux, are key to the transport to the upper troposphere and lower stratosphere. Second, I will show that stratosphere-to-troposphere transport of ozone plays an important role in understanding the surface ozone budget and thus air quality over the western U.S. and the mechanism underlying stratospheric intrusion is related to eastward propagating baroclinic waves.