Hybrid Data Assimilation Techniques and Applications
25 May 2016 | Contributor(s):: Erik Van Vleck
Data assimilation provides a framework for incorporating data or observations into models for both state space and parameter estimation. In this talk we discuss the development of some hybrid data assimilation techniques based upon shadowing refinement. These techniques employ dimension...
Simple models of the Indian summer monsoon
04 May 2016 | | Contributor(s):: Amit Apte
The Indian summer monsoon is a dramatic multiscale, multiphysics event that has a profound impact on the food security of more than a billion people. Predictions for the monsoon rainfall using present-day general circulation models are often wide of the mark, with serious consequences for the...
Vegetation patterns in mathematical models, and vegetation patterns in Horn of Africa
21 Apr 2016 | | Contributor(s):: Karna Gowda, Mary Silber
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....
Data assimilation for extreme ionospheric events: observing system experiments of the September 26, 2011 geomagnetic storm
14 Apr 2016 | | Contributor(s):: Juan Durazo
As increasingly sophisticated ground- and space-based technological systems that depend on the near-Earth space environment are being built, vulnerabilities to variations in the ionosphere are also increasing. These vulnerabilities are especially prominent during extreme space-weather events,...
Nonlinear dynamics of the El Niño Southern Oscillation
11 Mar 2016 | | Contributor(s):: Axel Timmermann
Currently, the strongest El Nino on record wreaks havoc across our planet, shifting global sea level and weather patterns and creating famines in South Africa and Central America. Other areas have experienced flooding which may have facilitated the outbreak of the mosquito-borne Zika virus...
Adaptive mesh refinement for storm surge modeling
03 Mar 2016 | | Contributor(s):: Marc Pierre Kjerland
Coastal inundation such as storm surge is a major concern for many of the world's population centers, and recent disasters such as Hurricane Sandy and Typhoon Haiyan highlight the growing risks of climate change. Numerical simulation of storm surge can be challenging due to the large spatial...
Local and non-local mechanisms of Arctic warming
25 Feb 2016 | | Contributor(s):: Vladimir Alexeev
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...
An application of Lagrangian data assimilation to Katama Bay, MA
02 Feb 2016 | | Contributor(s):: Laura Slivinski
Data assimilation is the process of combining predictions from numerical models with observations of the system. Fully Lagrangian data assimilation seeks to directly assimilate trajectories from drifters into some circulation model. This talk will provide a brief overview of Lagrangian data...
Early warning indicators for transitions in high-dimensional dynamical systems
17 Jan 2016 | | Contributor(s):: Henk Dijkstra
Two examples are presented. 1. Networks: The Atlantic Meridional Overturning (MOC), and 2. Transfer operators: Midlatitue Atmospheric Flow Transitions
New averaging results motivated by climate models: fat tails, oscillations, and tipping
10 Dec 2015 | | Contributor(s):: Rachel Kuske
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...
Global Warming Could Be Nonlinear
23 Nov 2015 | | Contributor(s):: Jonah Bloch-Johnson
It is widely acknowledged that many components of the Earth's climate system exhibit nonlinear behavior when forced, with examples ranging from ice sheets to ocean circulations to savanna. These changes, as profound as they are, are not expected to greatly impact global climate, as...
Modelling the Marginal Ice Zone
23 Nov 2015 | | Contributor(s):: Luke Bennetts
The marginal ice zone (MIZ) is the 10s to 100s of kilometres of partially ice-covered ocean, which sits between the open ocean and the quasi-continuous ice cover. It’s a highly dynamic region, where open ocean wave processes impact the ice cover, and it’s becoming larger and more...
Where's the Math in Climate Science?
09 Nov 2015 | | Contributor(s):: Christopher KRT Jones
Abstract: Climate science is dominated by the use of large-scale models, of which there are only 30 or so around the world. It might then seem that the need for mathematics is limited to areas that directly support the operation of such models. I will explain, by digging into the way the models...