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


Fall 2016 Schedule


September 13, 2016
       An Introduction to Energy Balance, Richard McGehee, School of Mathematics
       Earth's global mean surface temperature can be estimated using elementary physics: conservation of energy and the theory of black body radiation.
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September 20, 2016
       An Introduction to Budyko's Equation, Richard McGehee, School of Mathematics
       Budyko's equation of energy balance predicts the existence of stable ice caps for Earth's current climate.
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September 27, 2016
       Huybers' Model of Glacial Cycles, Somyi Baek, School of Mathematics
       In a 2007 paper, Huybers introduced a simple model exhibiting the changes in amplitude and frequency seen in the climate record (the mid-Pleistocne transition).
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October 4, 2016
       Huybers' Identification of Deglaciations, Cameron Thieme, School of Mathematics

Huybers introduced a computer algorithm to automatically pick out deglaciations from paleoclimate data. There are problems with using the algorithm on alternate data sets and on data sets from different geologic times.

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October 11, 2016
       Huybers' Model as a Filippov System, Somyi Baek, School of Mathematics
       Huybers' model can be viewed as Filippov system with a discontinuity boundary containing crossing regions as well as both attracting and repelling sliding regions.
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October 18, 2016
       Diffusive heat transport in the Budyko-Widiasih climate model, Jim Walsh, Oberlin College
       We consider Budyko's energy balance climate model with diffusive heat transport, coupled to Widiasih's ice line equation. We incorporate an albedo function appropriate for the extensive glacial episodes of the Neoproterozoic Era. We show that an approximating system of ODE exhibits a stable climate state with the ice line in tropical latitudes, provided the ice line moves slowly enough. With water remaining ice free about the equator, this Jormungand climate state has been proposed as an alternative to a snowball Earth.
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October 25, 2016
       Modeling species-environment interactions with limited information, Adam Clark, Department of Ecology, Evolution, and Behavior
       Though there is an abundant literature of mechanism-driven models describing various ecological and environmental processes, a perennial problem of applying these models to real-world systems is the scarcity of data. I will discuss a simplified resource competition model that we have used to predict species abundance in diverse prairie plant communities at the Cedar Creek Ecosystem Science Reserve in Bethel, MN. A major advantage of this model is that it can be parameterized using simple measurements taken in experimentally planted monocultures, yet makes accurate predictions about outcomes in diverse mixtures. To make these predictions, we take advantage of information from empirically observed tradeoffs among species functional traits, which helps constrain parameter estimates and improves model fit. I will also discuss ongoing efforts to extend the range of conditions across which this model is able to make accurate predictions, which could be useful for projecting impacts of environmental changes across unprecedented spatial and temporal scales.

Last update: October 21, 2016

©2016 Richard McGehee