Weakly Constrained Ensembles (WCE)
This package creates ensemble perturbations that have to satisfy an a priori linear constraint. It can also be used to create perturbations that are aware of the land-sea mask or that use space- (or time-) dependent correlation length.
Details of the procedure are explained in:
Barth, A., Alvera-Azcárate, A., Beckers, J.-M., Weisberg, R. H., Vandenbulcke, L., Lenartz, F., and Rixen, M.: Dynamically constrained ensemble perturbations – application to tides on the West Florida Shelf, Ocean Sci., 5, 259-270, 2009
Please cite this manuscript if you use this method in a publication.
- Extract the package at a location that suits you
- Add the path to your MATLAB/Octave search path in the menu File > Set Path (in MATLAB) or by adding:
in your start-up file called startup.m in MATLAB or .octaverc in GNU Octave.
The scripts wce_demo will show you several examples:
When using your own scripts, consider using the Matlab function “rng” to control the random numbers. E.g., call rng(‘shuffle’) before calling wce_simple.
- Perturbation aware of land-sea mask
- Perturbation with variable correlation length
- Perturbation aligned with vector field
- Perturbation constrained by harmonic shallow-water equations
The source code is available at http://data-assimilation.net/upload/WCE/WCE-1.0.tar.gz
Questions or problems ?
Please send an email to me (a dot barth at ulg dot ac dot be).