Earth
Richard McGehee
The Mathematics of Climate Change Seminar
University of Minnesota
School of Mathematics

 

Spring 2012 Schedule

 

 
 
   
   
January 17, 2012
       A Dynamical Systems Approach to a Conceptual Climate Model, Anna Barry, Boston University
       A coupled system consisting of an Energy Balance Model, moving iceline, and forcing due to greenhouse gases is explored using techniques from dynamical systems.
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January 25, 2012
       Widiasih's Theorem and a Few of its Consequences, Jim Walsh, Oberlin College
       Esther Widiasih has considered energy balance models from a dynamical systems perspective with considerable success. We present Widiasih's Theorem, along with applications thereof to variants of the standard Budyko-Sellers model.
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February 1, 2012
       An Estimate of the Widiasih Parameter, Richard McGehee, School of Mathematics
       Esther Widiasih introduced a dynamic ice line equation into the Budyko energy balance model. The equation contains a parameter controlling the rate at which the ice line advances and retreats. Paleoclimate data can be used to estimate the value of the parameter.
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February 8, 2012
       The Temperature Proxy Controversy, Larry Gray, School of Mathematics
       In 2010, the two statisticians McShane and Wyner published a paper in which they raised serious doubts about the way in which various "temperature proxies", such as tree ring and ice core data, have been used to estimate global mean temperatures from the past 1000 years. This paper caused such an uproar that an entire issue of the Annals of Applied Statistics was devoted to it, with about a dozen papers attacking and defending the work. This talk will be a mostly non-technical overview of the debate. Bring your hockey sticks.
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February 22, 2012
       Isotopes as Climate Proxies, Richard McGehee, School of Mathematics
       Isotopes of hydrogen, carbon, and oxygen are used extensively as proxies for temperature, ice volume, and biological activities. This presentation will be an introductory discussion of how they are measured and interpreted.
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February 29, 2012
       Milankovitch cycles as viewed through Budyko-Sellers' model during the Eocene, Samantha Oestreicher, School of Mathematics
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March 7, 2012
       Periodic fluctuations in deep water formation due to sea ice, Raj Saha, Mathematics and Climate Research Network
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March 21, 2012
       A report on Kerry Emanuel's paper, "A simple model of multiple climate regimes," Robert Foldes, School of Mathematics
       Reference: Emanuel, K. (2002), A simple model of multiple climate regimes, J. Geophys. Res., 107(D9), 4077, doi:10.1029/2001JD001002
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March 28, 2012
       The effect of carbon dioxide on Earth's radiation budget, Jim Walsh, Oberlin College
       An introductory talk on the radiation balance of planets and the effect atmospheric carbon dioxide has on this balance. A few remarks will be made concerning the outgoing long wave radiation term in Budyko's energy balance model.
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April 4, 2012
       Stommel's Ocean Circulation Box Model, Julie Leifeld, School of Mathematics
      

Reference: Henry Stommel. (1961), Thermohaline Convection with Two Stable Regimes of Flow, Tellus 13, 224-230, DOI: 10.1111/j.2153-3490.1961.tb00079.x

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April 18, 2012
       Ecosystem effects of CO2 concentration: a paper review on how C3 & C4 plants interact with CO2 concentration in paleodata, Samantha Oestreicher, School of Mathematics
      

Photosynthesis in C3 plants is different than that of C4 plants. C4 plants have adapted for low levels of CO2 while C3 plants prefer levels of atmospheric CO2 which are much higher than current values. The differences in plant functionality ought to be present in paleodata and global climate modeling attempts. We discuss these questions as addressed by the paper "Ecosystem effects of CO2 concentration: evidence from past climates" by I.C. Prentice and S. P. Harrison, DOI: 10.5194/cp-5-297-2009

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Last update: April 22, 2012 ©2012 Richard McGehee