The Use of Coherency to Improve Signal Detection in Dual-Polarization Weather Radars

Abstract

Currently, signal detection and censoring in operational weather radars is performed by using thresholds of the estimated signal-to-noise ratio (SNR) and/or the magnitude of the autocorrelation coefficient at the first temporal lag. The growing popularity of polarimetric radars prompts the quest for improved detection schemes that take advantage of the signals from the two orthogonally polarized electric fields. A hybrid approach is developed based on the sum of the cross-correlation estimates as well as the powers and autocorrelations from each of the dual-polarization returns. The hypothesis that ''signal is present'' is accepted if the sum exceeds a predetermined threshold; otherwise, the data are considered to represent noise and are censored. The threshold is determined by the acceptable rate of false detections that is less than or equal to a preset value. The scheme is evaluated both in simulations and through implementation on time series data collected by the research weather surveillance radar (KOUN) in Norman, Oklahoma.

Principles and applications of dual-polarization weather radar. Part I: Description of the polarimetric radar variables

“…The term "dual-polarimetric" is redundant, as the word "polarimetric" implies the use of polarization diversity for measurements; thus, "dual-polarimetric" should be avoided.3 Splitting the transmitted power between H and V channels results in a 3-dB loss in the signal-to-noise ratio compared to conventional WSR-88D radars. However, improved signal processing techniques (e.g.,Ivić et al 2009) have mitigated adverse effects of this 3-dB loss on signal detection and algorithm performance.…”

Use of Ground‐based Radar for Climate‐Scale Studies of Weather and Rainfall

“…Polarimetric radar will allow for improved rain rate estimation and precipitation‐type detection (Doviak et al. 2000; Ivic et al. 2009; Meischner 2004; Ryzhkov et al.…”

“…Current improvements to the WSR-88D units include modifications allowing radio waves emitted by the radar to have both horizontal and vertical orientations (Doviak et al 2000;Zrnic et al 2006). Polarimetric radar will allow for improved rain rate estimation and precipitation-type detection (Doviak et al 2000;Ivic et al 2009;Meischner 2004;Ryzhkov et al 2005a,b).…”

An Arithmetic to Enhance the Detecting Ability of Dual-polarization Weather Radar for Weak Echoes

“…In fact, the weak echo is a broad concept [5]. It can be indicated some echoes that radar does not detected for various reasons.…”