[PAOCQ] Robert Pincus (Columbia)

“The Kodachrome revolution: idealizations and understanding for stratospheric cooling with increasing CO2 and the role of clouds in a greenhouse atmosphere”

The combination of deep understanding of the physics controlling the flow of radiation though the atmosphere, increasingly detailed characterization of atmospheric state, and rapidly-expanding computational capabilities, has enabled ever-more-accurate calculations of radiation balance over the last decades. These computations underlie many of our expectations about the future including stratospheric cooling in response to increasing CO2 levels and more precipitation from a warming atmosphere… but they don’t tell us why these phenomena emerge. I will describe how the three key idealizations underlying the Kodachrome revolution – of spectroscopy, of radiative transfer, and of constraints imposed by the condensability of water vapor – are driving rapid progress in understanding of a wide range of behavior. I’ll show how the enormous spectral variation of absorption by water vapor and carbon dioxide are responsible a) for the cooling of the stratosphere and the resulting increase in top-of-atmosphere imbalance as CO2 concentrations are increased and b) for the surprising influence of water vapor and carbon dioxide on the radiation budget in fully cloudy skies.

PAOC Colloquium —

Interdisciplinary seminar series that brings together the whole PAOC (Program in Atmospheres, Oceans, and Climate) community. Seminar topics include all research concerning the physics, chemistry, and biology of the atmospheres, oceans and climate, as well as talks about societal impacts of climatic processes.

Contact: paoc-colloquium-comm@mit.edu