Circular depolarization ratio

The circular depolarization ( English circular depolarization ratio , CDR) is a polarimetric radar size and features in a radar with circular polarization, the logarithmic ratio of the reflectivity in the polarization plane with the same sense of rotation to the received echo signals with opposite directions of rotation. Similar to the linear depolarization ratio (LDR), it is used to classify the located objects. ${\displaystyle Z}$

${\displaystyle \mathrm {CDR} =10\log \left({\frac {Z_{\parallel }}{Z_{\bot }}}\right)}$

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Note that the CDR is defined inversely to the LDR ! Due to the higher proportion of the circularly polarized echo signal with opposite direction of rotation from a volume target made up of hydrometeors (raindrops), the CDR usually has a value of less than 1 (or in decibels : a negative value). Clouds , snow and fine rain achieve values ​​of around −30 dB, heavy rain around −20 dB. Point targets (aircraft) have a CDR of around 0 dB.

Individual proof

1. ↑ Nikolai Dotzek: Page no longer available , search in web archives: Radar meteorology. Part 05 Polarimetric radar quantities . Block lecture, FU Berlin, 1. – 5. March 2010, accessed July 17, 2010.