SABER

SABER is the System Agnostic Background Error Representation.

It provides generic software utilities for computing and working with the background error covariance matrix, often referred to as the B matrix.

SABER blocks

The B matrix is generally modeled as a series of linear operators, represented in SABER by “SABER blocks”. Such blocks, even if they come from different SABER components of SABER, are interoperable.

More details here:

• SABER blocks

SABER components

SABER blocks can encapsulate various components:

• BUMP: Background error on an Unstructured Mesh Package
• GSI: interface to the GSI covariance
• ID: identity operator
• SPECTRALB: spectral covariance/correlation
• StdDev: standard-deviation application
• mo_vertical_localization: Vertical localization as implemented in UK Met Office system

SABER applications

There are currently only two applications. The main application runs most of the functionality of saber and is called ErrorCovarianceToolbox. In addition we have an application that reads either an ensemble of states or perturbations. It then processes / filters the transformed increments, dumping them to file. More details are in

• The ProcessPerts Application

Calibration of SABER error covariance

A SABER error covariance can be calibrated from ensemble data:

• Calibration of a SABER error covariance model

SABER testing

SABER has its own pseudo-model for testing purposes, called QUENCH.

More details here:

• QUENCH
• SABER block testing

A low-level description of the classes, functions, and subroutines is also available, produced by means of the Doxygen document generator.

Doxygen Documentation