Quantile-Conserving Ensemble Filter Framework

The Quantile-Conserving Ensemble Filter Framework (QCEFF) tools are available in DART as of version v11. The DART development team (dart@ucar.edu) would be happy to hear about your experiences and is eager to build scientific collaborations using these new capabilities.

The QCEFF options are set using a qceff table given as a namelist option to &algorithm_info_nml.

&algorithm_info_nml
   qceff_table_filename = 'qceff_table.csv'

QCEFF options

QCEFF options are per quantity. For a given quantity, you specify the following options as columns of the qceff_table:

  • Observation error information

    Provides information about boundedness constraints that control the likelihood distribution associated with an observed variable when using perfect_model_obs to generate noisy observations.

    • bounded_below (default .false.)

    • bounded_above (default .false.)

    • lower_bound

    • upper_bound

  • Probit distribution information

    Used in the computation of the probit transform. The values needed are the bounds and the distribution type. These can be different for all three cases (inflation, state, and extended_state priors)

    • distribution (one of Available distributions)

    • bounded_below (default .false.)

    • bounded_above (default .false.)

    • lower_bound (default -888888)

    • upper_bound (default -888888)

  • Observation increment information

    • filter_kind (one of Available filter kinds)

    • bounded_below (default .false.)

    • bounded_above (default .false.)

    • lower_bound (default -888888)

    • upper_bound (default -888888)

Creating a qceff table

The table has two headers, row 1 and 2. The first row is the version number. The second row describes the QCEFF options corresponding to each column of the table. These two headers must be present in your qceff table. The truncated table below shows the table headers, and an example quantity QTY_TRACER_CONCENTRATION for the first 5 columns of the table. There is a complete table with all 25 columns in Google Sheets. You can copy and edit this table as needed.

To add a quantity, add a row to the table. For any quantity not listed in the table, the Default values values will be used for all 25 options. You only have to add rows for quantities that use non-default values for any of the input options. Ensure that there are no empty rows in between the quantities listed in the spreadsheet. Save your spreadsheet as a .csv file.

To run filter or perfect_model_obs, put the .csv file in the directory where you are running. Edit input.nml to set the algorithm_info_nml option qceff_table_filename, for example:

&algorithm_info_nml
   qceff_table_filename = 'qceff_table.csv'
truncated table

QCF table version: 1

QTY

bounded_below

bounded_above

lower_bound

upper_bound

QTY_TRACER_CONCENTRATION

.true.

.false.

0

-888888

Available filter kinds

  • EAKF (default)

  • ENKF

  • UNBOUNDED_RHF

  • GAMMA_FILTER

  • BOUNDED_NORMAL_RHF

  • KDE_FILTER

Available distributions

  • NORMAL_DISTRIBUTION (default)

  • BOUNDED_NORMAL_RH_DISTRIBUTION

  • GAMMA_DISTRIBUTION

  • BETA_DISTRIBUTION

  • LOG_NORMAL_DISTRIBUTION

  • UNIFORM_DISTRIBUTION

  • KDE_DISTRIBUTION

Default values

If a quantity is not in the qceff table, the following default values are used:

  • filter_kind (default EAKF)

  • dist_type (default NORMAL_DISTRIBUTION)

  • bounded_below (default .false.)

  • bounded_above (default .false.)

  • lower_bound (default -888888)

  • upper_bound (default -888888)

Note

-888888 is a missing value in DART.