Bayesian calibration of firn densification models

Impurity-controlled densification: a new model for stratified polar firn

A new densification model, which simulates the effect of impurities on the densification of polar firn, is presented. The classical densification models of Herron and Langway (1980) and Pimienta and Barnola (Barnola and others, 1991) are modified by assuming that the activation energy for deformation is reduced by the impurities. Motivated by recent observations, the impurity effect is formulat...

Firn Densification by Grain-boundary Sliding : a First Model

Densification in highly porous, isothermal firn occurs primarily by Newtonian sliding on grain boundaries, but the coordination number increases with density and restricts further sliding. At a relative density of about 0.6 the coordination number approaches 6 and sliding ceases to be a primary mechanism of densification; the resulting decrease in densification rate causes the critical point in...

Bayesian Calibration of Microsimulation Models.

Microsimulation models that describe disease processes synthesize information from multiple sources and can be used to estimate the effects of screening and treatment on cancer incidence and mortality at a population level. These models are characterized by simulation of individual event histories for an idealized population of interest. Microsimulation models are complex and invariably include...

Bayesian Calibration of Complex Computer Models

We consider prediction and uncertainty analysis for systems which are approximated using complex mathematical codes. Such models, implemented as computer codes, are often generic in the sense that by suitable choice of some of the model's input parameters the code can be used to predict behaviour of the system in a variety of speciic applications. However, in any speciic application the values ...

On the impact of impurities on the densification of polar firn