Release notes for PDAF

Version 1.9 - May 6, 2013

Changes:

• Added smoothers for ESKTF, ETKF, EnKF and the local filters LESTKF, LETKF.
• Added fixed basis (subtype=2) and fixed covariance matrix (subtype=3) variants for ESTKF, ETKF and the local filters LESTKF, LETKF.
• Added an example implementation of the offline mode with a simple 2D model domain and observations with data gaps. This implementation serves for a tutorial, that provides a step-by-step description on how to implement the analysis step in the offline mode.
• Added a function PDAF_get_memberid to query the index of an ensemble member during the forecast phase.
• revised the templates and simplified the implementation for the offline mode
• fixed a bug in SEIK/LSEIK for subtype=3

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Previous versions

Version 1.8 - February 12, 2012

Changes:

• Added Error Subspace Transform Kalman filter (ESTKF) and localized variant LESTKF. In addition a variant of the SEIK filter with symmetric square-root and explicit ensemble transformation is now available. (These filters have been introduced in the paper: "A unification of ensemble square-root filters" by L. Nerger, T. Janjic, J. Schroeter, and W. Hiller, Monthly Weather Review, 140, 2335-2345, ​doi:10.1175/MWR-D-11-00102.1)
• Added support to specify the type of the matrix square root in the SEIK filter. (Cholesky decomposition or symmetric square root based on singular value decomposition. The effects of these square root are also discussed in the paper mentioned above.)
• Revised the internal structure of PDAF to simplify the implementation of additional filters. (See the page about adding a filter algorithm for details.)
• Added support to compile for either double or single precision.
• Clean-up of PDAF's internal timers and memory allocation counting.

Version 1.7 - September 16, 2011

Changes:

• Revised internal structure of PDAF to simplify implementation of additional assimilation methods.
• Added full data assimilation implementation of Lorenz-96 model with PDAF.
• Revision of observation localization. It also includes the regulated localization that was introduced in the paper "A regulated localization scheme for ensemble-based Kalman filters" by L. Nerger et al. to appear in Q. J. Roy. Meteor. Soc. (accessible online: ​DOI:10.1002/qj.945)
• Added an option to display parameter options for a selected filter using the compiled program.
• Added routines with a simplified interface. The simplified interface does not require that you provide the names of user-supplied subroutines int he call to PDAF. However, one is restricted to use pre-defined routine names.
• License change: Now PDAF is licensed with the more flexible Lesser GNU Public License (older versions of PDAF used the GNU Public License).

Version 1.6.2 - 10/05/2010

Changes:

• Change in Makefiles to correct compilation on Linux with gfortran

Version 1.6.1 - 08/27/2010

Changes:

• Added pre-processor statement PDAF_NO_UPDATE to simplify tests during implementation.
• Unified interface to pre/poststep routines. For the EnKF Uinv was added. This array is never used in EnKF.
• Added shortened timer output to PDAF_print_info

Version 1.6.0 - 03/18/2010

Version distributed after presentation at Ocean Sciences Meeting, Portland, OR.

Changes:

• Added ETKF and LETKF to public release

Version 1.5.0 - 01/19/2010

Changes:

• Revised directory structure to separate PDAF core routines from test suite.

Versions 1.4.2 to 1.1.0

Version 1.0 - 10/08/2004

Original public release after participating at the GODAE International Summer School of Oceanography, „An Integrated View of Oceanography: Ocean Weather Forecasting in the 21st Century”, Lalonde les Maures, France