Linear depolarization ratio
From Glossary of Meteorology
linear depolarization ratio
(Abbreviated LDR.) The ratio of the power received in the orthogonal, or cross-polarized, channel to that received in the transmission, or copolarized, channel of a dual- channel radar, when a linearly polarized signal is transmitted.
Because the main component of the linearly polarized, backscattered signal from hydrometeors has the same polarization as the transmitted polarization, the linear depolarization ratio yields a value less than unity or, equivalently, a negative decibel quantity. Note that relative to the receiver channels of the radar the linear depolarization ratio is defined inversely to the circular depolarization ratio.