Contact: | Jeff Anderson |
Reviewers: | |
Revision: | $Revision: 1.5 $ |
Release Name: | $Name: pre_hawaii $ |
Change Date: | $Date: 2004/12/22 20:48:13 $ |
Change history: | see CVS log |
Main program for driving ensemble filter assimilations. This program provides a number of options that are driven from its namelist. The number of assimilation steps to be done are controlled by the input observation sequence and by the time-stepping capabilities of the model being used in the assimilation. This documentation was created for the H-release of DART.
types_mod obs_sequence_mod obs_def_mod time_manager_mod utilities_mod assim_model_mod random_seq_mod assim_tools_mod cov_cutoff_mod reg_factor_mod obs_model_mod ensemble_manager
We adhere to the F90 standard of starting a namelist with an ampersand '&' and terminating with a slash '/'.
namelist / filter_nml / & async, adv_ens_command, ens_size, cutoff, cov_inflate, start_from_restart, & output_restart, obs_sequence_in_name, obs_sequence_out_name, & restart_in_file_name, restart_out_file_name, init_time_days, init_time_seconds, & output_state_ens_mean, output_state_ens_spread, num_output_ens_members, & output_interval, num_groups, confidence_slope, outlier_threshold, & save_reg_series
This namelist is read in a file called input.nml
Contents | Type | Description |
---|---|---|
async | integer | Controls whether models are advanced via a subroutine call or by writing initial condition files for ensemble members to disk and having shellscript advance the model. Option: 0 = advance by subroutine; 1 = shell advance using shell script piped to filter; 2 = advance by F90 calls to shell to advance model. Default value is 0. |
ens_size | integer | Number of ensemble members to be integrated. Default is 20. |
cutoff | real(r8) | Cutoff controls a distance dependent weight that modulates the impact of an observation on a state variable. The units depend both on the location module being used and on the covariance cutoff module options selected. Default is 0.2. |
cov_inflate | real(r8) | Covariance inflation factor applied to prior estimate before each assimilation step. Default is 1.0 (no inflation). |
start_from_restart | logical | Should initial ensemble states come from a restart file. Default is .false. |
output_restart | logical | Should a restart file be written out for all ensemble members? Default is .false. |
obs_sequence_file_name | character(len=129) | File name that contains and observation sequence file. Default is 'obs_seq.in'. |
restart_in_file_name | character(len=129) | File name for a file containing restart state for all ensemble members. Default is 'filter_ics'. |
restart_out_file_name | character(len=129) | File name for output restart file. Default is 'filter_restart'. |
init_time_days | integer | Initial time of model (time is in days and seconds; see time_manager. If init_time_days and init_time_seconds are less than 0, the initial time comes from the time in the restart file. Default value is 0. |
init_time_seconds | integer | Initial time of model in seconds. Default is 0. |
output_state_ens_mean | logical | Output ensemble mean in state diagnostic files. |
output_state_ens_spread | logical | Output ensemble spread in state diagnostic files. |
output_obs_ens_mean | logical | Output ensemble mean in observation output file. |
output_state_ens_spread | logical | Output ensemble spread in observation output file. |
num_output_state_members | integer | This number of ensemble members is output to the state diagnostics file. If this is less than the total number of ensemble members the first subset is output. Default is 0. |
num_output_obs_members | integer | This number of ensemble members is output to the observation output file. If this is less than the total number of ensemble members the first subset is output. Default is 0. |
output_interval | integer | The frequency with which output state diagnostics are in assimilation times written. Default value is 1 meaning output is written at every observation time. |
num_groups | integer | Number of groups for hierarchical group filter. Should be a divisor of the ensemble size. Default is 1. |
confidence_slope | real(r8) | Controls strength of bias correction algorithm. See assim_tools module. Default is 0 (no correction). |
outlier_threshold | real(r8) | Discard all observations where the prior ensemble mean and the observation value differ by more than this many of the expected standard deviations. A quality control flag value is incremented by 10000 if this check is violated for the prior estimate. Negative value means no quality control of this kind. Default value is -1.0 |
save_reg_series | logical | Save statistics about the regression series for different observation / state variable pairs. Currently only minimally supported for non-parallel low-order models. Default is .false. |
Routine | Message | Comment |
---|---|---|
filter_generate_copy_meta_data | output metadata in filter needs ensemble size < 10000 | Ensemble sizes greater than require modifications to output ensemble code. |
Further development to better support observations that can only be computed once is needed.