Vegetation patterns in mathematical models, and vegetation patterns in Horn of Africa

21 Apr 2016 | Presentations

Visually striking large-scale spatial patterns of vegetation have been observed in semi-arid regions in the Americas, Africa and Australia. These have led to suggestions by theoretical ecologists that certain characteristics of the patterns may serve as early-warning signs of desertification....

Local and non-local mechanisms of Arctic warming

25 Feb 2016 | Presentations

Polar amplification (PA) is a prominent feature of currently observed and predicted future climate change suggested by both observations and models. We will discuss several PA mechanisms and feedbacks in the ocean and the atmosphere suggested by different researchers and connect it to the real...

New averaging results motivated by climate models: fat tails, oscillations, and tipping

10 Dec 2015 | Presentations

We review recent results where new averaging approaches are developed and applied in the context of systems with multiple time scales and fat tails  and in non-autonomous multiple scale systems with oscillatory forcing.  These types of systems appear in a variety of higher dimensional...

Jafarov Seminar

30 Nov 2015 | Presentations

Dr. Elchin Jafarov is a research associate at the National Snow and Ice Data Center, at the Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder. He has a PhD in Geophysics and a masters degree in Mathematics both from the University of Alaska Fairbanks....

Tipping points and power cuts

18 Jun 2015 | Presentations

Who, or what, will tip the big climate models?

18 Jun 2015 | Presentations

ICMS Tipping Points: Fundamentals and Applications

13 Jun 2015 | Workshops

Objectives: This workshop (September, 2013) brings together mathematicians and statisticians, whose research expertise is relevant to investigating threshold behaviour in complex environmental systems, with the climate scientists and ecologists who exploit mathematical modelling in their research...

Orbital Forcing and Ice Age

02 Jun 2015 | Educational Materials

Annotated Bibliography by Daniel Koll

Midwest Mathematics and Climate Conference - Day 2 Afternoon Session

12 May 2015 | Presentations

Charles Jackson, University of Texas, AustinDual-state Behavior of the Community Climate System ModelIce age climate between 80,000 and 11,000 years ago experienced abrupt (< 10 year) global-scale climate transitions every few thousand years. Evidence and theory suggests such behavior may be...

Midwest Mathematics and Climate Conference

12 May 2015 | Workshops | Contributor(s): Richard McGehee

The conference is sponsored by the National Science Foundation, Institute of Mathematics and Its Applications, the Office of Research,College of Liberal Arts and Sciences, and the Department of Mathematics, Department of Geography/Atmospheric Science Program, and The...

Midwest Mathematics and Climate Conference

12 May 2015 | Workshops

The conference is sponsored by the National Science Foundation, Institute of Mathematics and Its Applications, the Office of Research,College of Liberal Arts and Sciences, and the Department of Mathematics, Department of Geography/Atmospheric Science Program, and The...

Midwest Mathematics and Climate Conference

12 May 2015 | Workshops

The conference is sponsored by the National Science Foundation, Institute of Mathematics and Its Applications, the Office of Research,College of Liberal Arts and Sciences, and the Department of Mathematics, Department of Geography/Atmospheric Science Program, and The...

Midwest Mathematics and Climate Conference - Day 1 Afternoon Session

12 May 2015 | Presentations

Graham Feingold, National Oceanic & Atmospheric AdministratonDynamical System Analogues to Cloud SystemsShallow convection exhibits fascinating cellular structures at scales of a few to several hundred kilometers. Configurations of relatively cloud free open cell states, or much cloudier...

Realistic modeling and analysis of synchronization dynamics in power-grid networks

08 May 2015 | Presentations | Contributor(s): Mary Lou Zeeman

An imperative condition for the functioning of a power-grid network is that its power generators remain synchronized. Disturbances can prompt desynchronization, which is a process that has been involved in large power outages. In this talk I will first give a comparative review of three leading...

Synchronization in power grid networks

07 May 2015 | Presentations | Contributor(s): Mary Lou Zeeman

This survey discusses Master Stability Function (MSF) analysis for determining stability of synchronization of coupled oscillators on network. In addition, we briefly discuss the derivation of the Swing equation that determine the dynamics of a node in power grid network, and...

Complex Energy Systems

07 May 2015 | Presentations | Contributor(s): Mary Lou Zeeman

This is the opening guest lecture for the Electric Grid Focus Group.  Dr. Michael Chertkov of Los Alamos National Lab describes the statistical and mathematical problems arising in complex energy systems, including the electric grid and gas networks.  Systems with high penetration of...

A Survey of Grid Control and Optimization

07 May 2015 | Presentations | Contributor(s): Mary Lou Zeeman

This is an introductory survey of how control problems arise on different time scales in electric grid transmission problems.  The set up and general form of such problems are considered, along with operational considerations.

Particle filters for geophysical applications

30 Apr 2015 | Presentations | Contributor(s): Mary Lou Zeeman

Avoiding degeneracy is a crucial challenge for particle filters. Results have shown that the number of particles scales exponentially with respect to the number of independent observations. In this talk I will review attempts to counteract this phenomenon by exploiting proposal densities. I will...

Toward a hybrid particle-ensemble Kalman filter for assimilating data from Lagrangian instruments into high dimensional models

30 Apr 2015 | Presentations | Contributor(s): Mary Lou Zeeman

Presented by Elaine Spiller on 3-26-15Abstract:We discuss a recently proposed hybrid particle-ensemble Kalman filter for assimilating Lagrangian data, and apply it to a high-dimensional quasi-geostrophic ocean model. Effectively the hybrid filter applies a particle filter to the highly nonlinear,...

Emulators in climate science. Uncertainty, sensitivity, calibration and more

30 Apr 2015 | Presentations | Contributor(s): Mary Lou Zeeman

An emulator or a surrogate is a statistical approximation of a complex numerical model. Emulators are fast to run and include a measure of their own uncertainty. This makes them suitable for a number of applications in climate science. Emulators were originally devised for uncertainty...