Hybrid EnKF and Particle Filter: Langrangian DA and Parameter Estimation

02 Jun 2016

This is a talk delivered at the Imperial College meeting on Stochastic Modeling in GFD, Data Assimilation and Non-equilibrium Phenomena on 11-4-2015.  This talk presents joint research by Chris Jones at UNC-CH and Naratip Santitissandeekorn on hybrid data assimilation methods.

A Tutorial on Kalman Filters

01 Jun 2016

This is an introduction to the Kalman filter, explaining some underlying assumptions, use and extensions of the method.This talk was given on 10-7-2015.

Data assimilation for extreme ionospheric events: observing system experiments of the September 26, 2011 geomagnetic storm

14 Apr 2016 | Presentations

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,...

Hybrid EnKF and Particle Filter: Lagrangian DA and Parameter Estimation

06 Nov 2015 | Presentations

Dealing with high dimensional systems is one of the central problems of data assimilation.  A strategy is proposed here for systems that enjoys a skew-product structure.   Christopher Jones, University of North Carolina at Chapel Hill, presents joint work with Naratip...

OptIC project: An intercomparison of optimization techniques for parameter estimation in terrestrial biogeochemical models

20 Sep 2015 | Educational Materials

A comparison of different optimization techniques for parameter estimation for a very simple ecosystem model (2 ODEs).

The REFLEX project: Comparing different algorithms and implementations for the inversion of a terrestrial ecosystem model against eddy covariance data

20 Sep 2015 | Educational Materials

A comparison of parameter estimation techniques for a simplified ecosystem model.  A follow-on to the OpTIC study with a more complex model (DALEC).

Midwest Mathematics and Climate Conference - Day 2 Morning Session

12 May 2015 | Presentations

Juan Restrepo, Oregon State UniversityData AssimilationAccounting for uncertainties has led us to alter our expectations of what is predictable and how such predictions compare to nature. A significant effort, in recent years, has been placed on creating new uncertainty quantification techniques,...

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...

Introduction to the Mathematics of Climate at UMN - Lecture 18

12 May 2015 | Presentations

This is lecture 18 in the series "Introduction to the Mathematics of Climate" offered at the University of Minnesota in 2014 with the support of MCRN and The Institute for Mathematics and its Applications.

Introduction to the Mathematics of Climate at UMN - Lecture 14

12 May 2015 | Presentations

This is lecture 14 in the series "Introduction to the Mathematics of Climate" offered at the University of Minnesota in 2014 with the support of MCRN and The Institute for Mathematics and its Applications.  

IMA Hot Topics Workshop: Predictability in Earth System Processes

09 May 2015 | Workshops

A major question facing climate modeling is how best to incorporate data into models. As climate models increase in complexity, their results become correspondingly intricate. Such models represent climate processes spanning multiple spatial and temporal scales and must relate disparate physical...

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

08 May 2015 | Presentations

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...

Introduction to the Mathematics of Climate

07 May 2015 | Series

This course will investigate the following questions from a mathematical perspective. What determines the Earth's surface temperature? Why does the carbon dioxide in the atmosphere affect the climate? How do changes in the Earth's orbital parameters change the climate? Why has the Earth...

Complex Energy Systems

07 May 2015 | Presentations

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...

Complex Phytoplankton Dynamics: The Mathematical Perspective

04 May 2015 | Educational Materials

Bibliography by Arjen Doelman and Antonios Zagaris to accompany tutorial lecture on Phytoplankton-Nutrient Modeling at the 2011 MBI Workshop on Ocean Ecologies and their Physical Habitats in a Changing Climate, and the follow-on lectures on Phytoplankton growth in oligotrophic oceans: Linear...

Particle filters for geophysical applications

30 Apr 2015 | Presentations

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

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

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...

Statistical Data Assimilation For Parameter Estimation In Costal Ocean Hydrodynamics Modeling

30 Apr 2015 | Presentations

Coastal ocean models are used for a variety of applications, including modeling tides and hurricane storm surge. These models numerically solve the shallow water equations, which are derived by depth integrating the Navier-Stokes equations. The inherent uncertainties in coastal ocean models are a...