Calendar Event Details

610 Atmospheres Seminar: James G. Anderson

Affiliation: Harvard University
Event Date: Thursday, March 21, 2013

Location: B33:H114
Time: 3:30 PM

Climate Forcing and Free Radical Response: Convective Injection of Water Vapor Into the Summertime Stratosphere at Mid-Latitudes

Evidence is presented, based on both in situ and satellite observations, that convective injection of water vapor occurs over the US in summer. The injected water vapor satisfies conditions required to induce a chemical shift leading to the rapid conversion of inorganic chlorine to free radical form. These observations raise a series of questions: What is the convective physics that can deliver this depth and frequency of injection of water vapor?  How will the frequency and intensity of that deep convective injection respond to increased forcing of the climate by CO2 and CH4? Within the domain of convectively injected water vapor, what other source molecules (organic bromines, chlorines, hydrocarbons, heavy metals, etc.) are present in the injected air-mass capable of carrying radical precursors into the stratosphere that could significantly accelerate the catalytic destruction of ozone? What are the implications for secular trends in summer UV dosage levels over mid-latitudes of the NH? How rapidly is ClO converted back to HCl and ClONO2 in the summertime lower stratosphere at mid-latitudes?  What is the quantitative role of BrO in the time integrated removal of ozone? How rapidly does NOx recover? What are the implications for Solar Radiation Management (SRM) strategies for decreasing the shortwave forcing of the Earth’s climate system? What evidence is there in the paleo-record related to this phenomenon?

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Posted or updated: Wednesday, March 13, 2013

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