A filter that creates a string variable that makes it simpler to identify Atmospheric Motion Vector (AMV) / Satwind observations by combining satellite and channel information.
This is useful for later AMV processing where we want to apply filters to subsets of observations.
To identify the type of motion that has been tracked, AMV BUFR observations are supplied with a channel central frequency (Hz) and a wind computation method:
002023 SATELLITE DERIVED WIND COMPUTATION METHOD
- 0 Reserved
- 1 INFRARED MOTION OBSERVED IN THE INFRARED CHANNEL
- 2 VISIBLE MOTION OBSERVED IN THE VISIBLE CHANNEL
- 3 VAPOUR CLOUD MOTION OBSERVED IN THE WATER VAPOUR CHANNEL
- 4 COMBINATION MOTION OBSERVED IN A COMBINATION OF SPECTRAL CHANNELS
- 5 VAPOUR CLEAR MOTION OBSERVED IN THE WATER VAPOUR CHANNEL IN CLEAR AIR
- 6 OZONE MOTION OBSERVED IN THE OZONE CHANNEL
- 7 VAPOUR MOTION OBSERVED IN WATER VAPOUR CHANNEL (CLOUD OR CLEAR)
- 13 Root-mean-square
The most common use of the wind computation method is to distinguish between clear-sky and cloudy water vapour targets.
This filter combines this channel information, together with the satellite name, to create a string that defines the satellite/channel combination of each observation. We also output a diagnostic variable which provides information on unidentified satellites or channels.
Required :
- "MetaData", "sensor_central_frequency"
- "MetaData", "satellite_identifier"
- "MetaData", "wind_computation_method"
Outputs:
- "MetaData", "satwind_id"
- "Diag", "satwind_id"
Example: The following yaml will attempt to identify two infrared channels with computation method value of 1 and central frequencies falling betwen the min and max frequency bounds. If there are observations that match these conditions they are labelled with the respective "wind channel" string. If observations are identified from GOES-16 (platform number 270) they are also labelled with the respective "Sat name" string. This will fill MetaData/satwind_id with values "GOES16ir112","GOES16ir38" if these are present in the observations. If either the satellite or channel are not identified, then MetaData/satwind_id is set to "MISSING". To help track down why observations are set to missing we also output a diagnostic string variable, Diag/satwind_id. When the observation is not identified, this has the form: id<satellite identifier>_comp<cloud motion method>_freq<central frequency>. E.g. if the satellite is identified but the channel is not: "GOES16_comp3_freq0.484317e14", if the satellite is not identified but the channel is: "id270ir112".
obs filters:
- filter: satname
SatName assignments:
- min WMO Satellite id: 1
max WMO Satellite id: 999
Satellite_comp:
- satobchannel: 1
min frequency: 2.6e+13
max frequency: 2.7e+13
wind channel: ir112
- satobchannel: 1
min frequency: 7.5e+13
max frequency: 8.2e+13
wind channel: ir38
Satellite_id:
- Sat ID: 270
Sat name: GOES16
Implements ufo::FilterBase.
Definition at line 147 of file SatName.cc.