ChannelUseflagCheckRad

An important feature of interest when assimilating radiances is the selection of the channels to be assimilated. This can be performed through the usage of the ChannelUseflagCheckRad function. This function rejects observations whose values are set to less than one.

Required input parameters:

channels

List of channels available for assimilation.

use_flag

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

Example configuration:

- filter: Bounds Check
  filter variables:
  - name: brightnessTemperature
    channels: 4-6
  test variables:
  - name: ObsFunction/ChannelUseflagCheckRad
    channels: 4-6
    options:
      channels: 4-6
      use_flag: [ 1, -1,  1 ]
  minvalue: 1.0e-12
  action:
    name: reject

In the above example the filter checks if brightness temperature for channels 4, 5 and 6 are expected to be used. Suppose we have the following observation data with 3 locations and 4 channels:

• channel 3: [100, 250, 450]

• channel 4: [250, 260, 270]

• channel 5: [200, 250, 270]

• channel 6: [340, 200, 250]

In this example, all observations from channel 3 will pass QC because the filter isn’t configured to act on this channel. All observations for channels 4 and 6 will pass QC because these channels are set to 1, while all observations for channel 5 will be rejected because that channel is set to -1.