CLogZ
The CLOGZ is a two dimensional representation of the radar data in "dBZ".
It is derived from the Doppler scan. The C in the CLOGZ stands for the
"correction" for ground clutter that is made in the radar signal processor.
Ground clutter is suppressed. There is also "uncorrected" or UCLOGZ data
in the Doppler scans. This is sometimes called "total reflectivity" and
it has not been suppressed for ground clutter. This is also what is in
the Conventional Volume scan. The difference between UCLOGZ and CLOGZ
is the power due to the clutter and it is called the CSR or Clutter to Signal
Ratio. In the signal processor, a CSR of around 25 dBZ (radar dependent)
is used to filter out data that has a lot of clutter in it as defined by CSR.
Within this product, a lower CSR ratio is used to filter out more data as well
- typically 18 dBZ is used, but this is dependent on the radar as well.
Different thresholds are used for reflectivity and the velocity.
There is an SQI filter on the radial velocity data, so it is possible to have
radial velocity data and not reflectivity data. For operational interpretation,
it is confusing to have valid data on one image and not on the corresponding
reflectivity or radial velocity image, so there is a requirement when producing
the CLOGZ product that there be valid radial velocity data at the same radar
bin.
Example of CLogZ image at 0.5°