Wednesday 19 Mar 2014Inaugural Lecture - stratospheric influence on weather and climate: from snow in London to droughts in Australia

Professor Mark P Baldwin - Mathematics and Computer Science, University of Exeter

Harrison LT 004 (and via video conference Peter Lanyon LT2, Penryn) 17:15-19:00

Until the late 1990s, it was assumed that the cold, nearly cloudless stratosphere had little or no effect on weather and climate at Earth's surface. Two observations have shown that this viewpoint is incorrect. First, stratospheric variability is associated with substantial effects on Northern Hemisphere weather and climate - such as shifts in the jet streams, storm tracks and precipitation. Second, ozone loss in the Southern Hemisphere has cooled and strengthened the stratospheric polar vortex, which is associated with long-term shifts in jets, storm tracks, and precipitation patterns.

Despite unambiguous observations of this phenomenon, as well as numerical simulations, a clear physical explanation of this downward coupling remains elusive. Using observational data, I will argue that the primary dynamical mechanism is simply the movement of stratospheric mass into and out of the polar cap. This movement of mass in the stratosphere can be likened to the movement of mass around a waterbed. The surface of the waterbed (tropopause) is depressed where mass is added, which directly affects the tropospheric circulation.

PROFESSOR MARK BALDWIN is the Head of Mathematics and Computer Science at the University of Exeter. He joined the University in May 2012 as Chair in Climate Science, having previously served as Vice President and Senior Research Scientist at Northwest Research Associates (NWRA) in Seattle, USA. NWRA is a private company specializing in basic and applied research in the geophysical sciences.

Mark's training is as an atmospheric scientist and applied mathematician, having earned his PhD at the University of Washington, Seattle. His research is focused on the role of the stratosphere in the climate system, in particular how ozone loss, increasing greenhouse gases, and natural variability of the stratosphere affect surface weather and climate on a timescale from ten days to centuries. He is particularly interested in understanding the dynamical mechanisms by which changes to the stratosphere can have substantial effects at Earth's surface, as well as exploiting this relationship to improve weather forecasts.

He is a Fellow of the Royal Meteorological Society, and a member of the London Mathematical Society and the Royal Statistical Society.

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