Contact: | Jeff Anderson |
Reviewers: | |
Revision: | $Revision: 1.5 $ |
Release Name: | $Name: post_iceland $ |
Change Date: | $Date: 2005/06/08 17:07:18 $ |
Change history: | see CVS log |
Computes the weight with which an observation should impact a state variable that is separated by a given distance. The distance is in units determined by the location module being used.
types_mod utilities_mod
use cov_factor_mod, only : | comp_cov_factor |
Optional namelist interface &cov_cutoff_nml may be read from file input.nml.
real(r8) :: comp_cov_factor real(r8), intent(in) :: z_in real(r8), intent(in) :: c real(r8), optional :: localization_override
Returns a weighting factor for observation and state variable separated by distance z_in and with a half-width distance, c. Three options are provided and controlled by a namelist parameter. The optional argument localization_override controls the type of localization if it is present.
z_in | The distance between an observation and state variable. |
c | Factor that describes the localization function. Describes the half-width of the functions used here. |
localization_override | Controls localization type if present. Same values as for namelist control. |
var | Covariance value returned. |
We adhere to the F90 standard of starting a namelist with an ampersand '&' and terminating with a slash '/'.
namelist / cov_cutoff_nml / select_localization
Contents | Type | Description |
---|---|---|
select_localization | integer | Selects the localization function. 1 = Gaspari-Cohn 5th order polynomial with halfwidth c. 2 = Boxcar with halfwidth c (goes to 0 for z_in > 2c). 3 = ramped boxcar. Has value 1 for z_in < c and then reduces linearly to 0 at z_in = 2c. |
Routine | Message | Comment |
---|---|---|
comp_cov_factor | Illegal value of "select_localization" in cov_cutoff_mod namelist | Only values 1 through 3 select a localization function. |