MODULE reg_factor

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$Id: reg_factor_mod.html 11403 2017-03-27 23:26:22Z hendric@ucar.edu $

INTERFACES / NAMELIST / FILES / REFERENCES / ERRORS / PLANS / PRIVATE COMPONENTS / TERMS OF USE

Overview

Computes a weighting factor to reduce the impact of observations on state variables using information from groups of ensembles. Can be run using groups or using archived summary information available from previous group filter experiments.

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OTHER MODULES USED

types_mod
utilities_mod
time_manager_mod
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PUBLIC INTERFACES

use reg_factor_mod, only : comp_reg_factor

A note about documentation style. Optional arguments are enclosed in brackets [like this].


var = comp_reg_factor(num_groups, regress, obs_index, state_index [, obs_state_ind] [, obs_state_max])
real(r8)                                    ::  comp_reg_factor 
integer,                         intent(in) ::  num_groups 
real(r8), dimension(num_groups), intent(in) ::  regress 
integer,                         intent(in) ::  obs_index 
integer,                         intent(in) ::  state_index 
integer, optional,               intent(in) ::  obs_state_ind 
integer, optional,               intent(in) ::  obs_state_max 

Returns a weighting factor given regression factors from each group of a group filter or retrieves a factor generated by previous group filter runs from a file.

num_groups    Number of groups. Set to 1 when using information from previously run group filter from file.
regress    Regression factor from each group for a given state variable and observation variable pair.
obs_index    Integer index of the observation being processed. Not used in current implementation .
state_index    Integer index of state variable being processed. Not used in current implementation.
obs_state_ind    Index into file generated for Bgrid model which could be duplicated in other large models.
obs_state_max    Maximum number of observation state variable pairs with non-zero impacts for a given model and observation sequence. Used for generating Bgrid statistic files.

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NAMELIST

This namelist is read from the file input.nml. Namelists start with an ampersand '&' and terminate with a slash '/'. Character strings that contain a '/' must be enclosed in quotes to prevent them from prematurely terminating the namelist.

&reg_factor_nml
   select_regression    = 1,
   input_reg_file       = "time_mean_reg",
   save_reg_diagnostics = .false.,
   reg_diagnostics_file = "reg_diagnostics"  
/


Item Type Description
select_regression integer Selects the method for computing regression factor.
  • 1 = compute using sampling theory for any ensemble size.
  • 2 = low order model format. Works from archived time mean or time median regression files generated by low-order models like Lorenz-96.
  • 3 = selects bgrid archived file. This is not currently supported in released versions.
input_reg_file character(len=129) File name from which statistics are to be read for select_regression = 3.
save_reg_diagnostics logical  True if regression diagnostics should be computed.
reg_diagnostics_file character(len=129)  File name to which to write diagnostics.


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FILES

filename purpose
from input.nml&reg_factor_mod:input_reg_file file of regression coefficients
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REFERENCES

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ERROR CODES and CONDITIONS

RoutineMessageComment
comp_reg_factor Illegal value for namelist parameter select_regression Value must be 1(sampling theory), 2 (table lookup) or 3 (read from obs_state_reg_file).

KNOWN BUGS

none at this time

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FUTURE PLANS

none at this time

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PRIVATE COMPONENTS

N/A

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Terms of Use

DART software - Copyright UCAR. This open source software is provided by UCAR, "as is", without charge, subject to all terms of use at http://www.image.ucar.edu/DAReS/DART/DART_download

Contact: DART core group
Revision: $Revision: 11403 $
Source: $URL: https://svn-dares-dart.cgd.ucar.edu/DART/releases/Manhattan/assimilation_code/modules/assimilation/reg_factor_mod.html $
Change Date: $Date: 2017-03-27 17:26:22 -0600 (Mon, 27 Mar 2017) $
Change history:  try "svn log" or "svn diff"