
Hybrid EnKF and Particle Filter: Langrangian DA and Parameter Estimation
02 Jun 2016  Contributor(s):: Christopher KRT Jones, naratip santitissadeekorn
This is a talk delivered at the Imperial College meeting on Stochastic Modeling in GFD, Data Assimilation and Nonequilibrium Phenomena on 1142015. This talk presents joint research by Chris Jones at UNCCH and Naratip Santitissandeekorn on hybrid data assimilation methods.

A Tutorial on Kalman Filters
01 Jun 2016  Contributor(s):: Colin James Grudzien
This is an introduction to the Kalman filter, explaining some underlying assumptions, use and extensions of the method.This talk was given on 1072015.

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 reduction...

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 spacebased technological systems that depend on the nearEarth space environment are being built, vulnerabilities to variations in the ionosphere are also increasing. These vulnerabilities are especially prominent during extreme spaceweather events,...

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...

Hybrid EnKF and Particle Filter: Lagrangian DA and Parameter Estimation
06 Nov 2015   Contributor(s):: Naratip Santitssadeekorn, Christopher KRT Jones
Dealing with high dimensional systems is one of the central problems of data assimilation. A strategy is proposed here for systems that enjoys a skewproduct structure. Christopher Jones, University of North Carolina at Chapel Hill, presents joint work with Naratip...

Midwest Mathematics and Climate Conference  Day 2 Morning Session
12 May 2015 
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  Day 1 Afternoon Session
12 May 2015 
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 powergrid networks
08 May 2015   Contributor(s):: Takashi Nishikawa
An imperative condition for the functioning of a powergrid 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...

Complex Energy Systems
07 May 2015   Contributor(s):: Michael Chertkov
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...

Particle filters for geophysical applications
30 Apr 2015   Contributor(s):: Javier Amezcua
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 particleensemble Kalman filter for assimilating data from Lagrangian instruments into high dimensional models
30 Apr 2015   Contributor(s):: Elaine Spiller
Presented by Elaine Spiller on 32615Abstract:We discuss a recently proposed hybrid particleensemble Kalman filter for assimilating Lagrangian data, and apply it to a highdimensional quasigeostrophic 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   Contributor(s):: Peter Challenor
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   Contributor(s):: Talea Mayo
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 NavierStokes equations. The inherent uncertainties in coastal ocean models are a...

Correlated Observation Errors in Data Assimilation
30 Apr 2015   Contributor(s):: Sarah Dance
Remote sensing observations often have correlated errors, but the correlations are typically ignored in data assimilation for numerical weather prediction. The assumption of zero correlations is often used with data thinning methods, resulting in a loss of information, and reduction in analysis...

Ionospheric weather forecasting using the LETKF
23 Mar 2015   Contributor(s):: Juan Durazo
We track the threedimensional global distribution of electron density in the ionosphere using theLocal Ensemble Kalman Filter (LETKF) and the ThermosphereIonosphereElectrodynamics GlobalCirculation Model (TIEGCM) by assimilating globally distributed electron density profiles. TheTIEGCM is a...

An Introduction to Lagrangian Data Assimilation  Part II
23 Mar 2015   Contributor(s):: Laura Slivinski
Lauara Slivinski at Woods Hole Oceanographic Institution gives an introduction to Lagrangian Data Assimilation on 11132014.

An Introduction to Lagrangian Data Assimilation  Part I
23 Mar 2015   Contributor(s):: Laura Slivinski
Laura Slivinski at Woods Hole Oceanographic Institute gives an introduction to Lagrangian Data Assimlation on 10302014.

Andy Reagan: Masters Thesis
23 Mar 2015   Contributor(s):: Andy Reagan
Andy Reagan at UVM gives a talk about his masters work on uncertainty quantification and data assimilation to improve the numerical prediction of fluids in the thermosyphon. This talk will involve several data assimilation methods, including variational techniques, but will focus on LETKF....

An Introduction to Variational Data Assimilation
23 Mar 2015   Contributor(s):: Naratip Santitissadeekorn
Naratip Santitissadeekorn gives an introductory survey of variational techniques in data assimilation including 3DVAR and 4DVAR. This talk was given on 10214.