ObsErrorFactorQuotient¶
This obsfunction was designed to mimic GSI Observer method of rejecting observations when
the ratio of final ObsError, after inflation, is more than a threshold amount greater than
the starting ObsError. The ObsFunction is a simple division expected to be used with
Bounds Check
filter above a maximum threshold.
Options¶
numerator
(withname
)the variable and group name to be used in the numerator.
denominator
(withname
)the variable and group name to be used in the denominator.
Example¶
- Filter: Bounds Check
filter variables:
- name: airTemperature
action:
name: reject
maxvalue: 3.6
test variables:
- name: ObsFunction/ObsErrorFactorQuotient
options:
numerator:
name: ObsErrorData/airTemperature # After inflation step
denominator:
name: ObsError/airTemperature
defer to post: true # Likely necessary for order of filters
In this example, the observations of airTemperature
are rejected when the final
ObsError is 3.6 times larger than the original ObsError due to one or more prior series
of error inflation steps. The usage of defer to post
option helps to ensure that
earlier QC steps in the yaml that may inflate the ObsError will occur before this filter is run.