Atmosphere Ocean Science Colloquium

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Understanding and quantifying the stratospheric circulation using age of air

Speaker: Marianna Katherine Linz, MIT

Location: Warren Weaver Hall 1302

Date: Wednesday, September 20, 2017, 3:30 p.m.

Synopsis:

The circulation of the stratosphere transports trace gases, such as water vapor and ozone, which impact surface climate. This circulation cannot be measured directly, and so it is usually qualitatively inferred from trace gas distributions. I present the derivation of new theory that quantitatively relates the circulation to the idealized tracer "age" of air. Age is a measure of how long the air has been in the stratosphere since it was last at the tropopause, and it has unique mathematical properties that are exploited in this theory. Age can be calculated using observations of trace gases with concentrations that are linearly increasing in time in the troposphere. I have applied this theory to calculate the global circulation strength from two satellite data products, and I will present these results and a comparison with a state of the art model