InterChannelConsistencyCheck

The Inter-channel consistency check is another feature of interest when assimilating radiances. This check is performed through the InterChannelConsistencyCheck function. Currently, this function is implemented for AMSU-A and ATMS platforms, and performs a check over a group of channels depending on the instrument. For AMSU-A, it considers the channels 1-6 and 15, while for ATMS the channels 1-7 and 16-18. The function internally converts effective observation error to inverse of the error variance and checks if one of the channels is being rejected, if so, all channels in the group are rejected for a given location.

Required input parameters:

channels

List of channels available for assimilation.

sensor

Name of the sensor for which the observation error factor applies.

use_flag

Useflag (-1: not used; 0: monitoring; 1: used) for each channel in channels.

Optional Input parameters:

test_obserr

Name of the data group to which the observation error is applied (default: ObsErrorData).

test_qcflag

Name of the data group to which the QC flag is applied (default: QCflagsData).

Example configuration:

- filter: Bounds Check
  filter variables:
  - name: brightness_temperature
    channels: 1-15
  test variables:
  - name: InterChannelConsistencyCheck@ObsFunction
    channels: 1-15
    options:
      channels: 1-15
      sensor: amsua_n19
      use_flag: [ 1,  1,  1,  1,  1,
                  1, -1, -1,  1,  1,
                  1,  1,  1, -1,  1 ]
  maxvalue: 1.0e-12
  action:
    name: reject

The above example is for AMSU-A N19 (amsua_n19), and the filter checks if any of the brightness temperature for channels 1-6 and 15 are being rejected, if so, all the channels 1-6 and 15 are rejected for a given location.