Sensitivity of Radar Variables to Signal-to-Noise Ratio in Dual-Polarization Weather Radar
Dual-polarization Doppler weather radar variables such as differential reflectivity (ZDR), differential propagation phase shift (ΦDP), specific differential phase (KDP), and the co-polar correlation coefficient (ρHV), which are closely related to the characteristic of hydrometeors. The precision of these variables determines the accuracy for quantitative precipitation estimation (QPE) and hydrometeor classification. By analyzing the relationship between the polarimetric radar variables and the signal-to-noise ratio (SNR), it is found that when the SNR decreases to a certain threshold, polarimetric variables become more sensitive to the decrease in the SNR, and the precision of these variables become deteriorated with the decrease of the SNR. This threshold usually is closely related to the radar performance, for the X-band dual-polarization radar used in this paper, the SNR threshold is about 20 dB. The results of this study can provide some reference for radar system performance evaluation and data quality control.
KeywordsDual-polarization Doppler weather radar The Signal-to-Noise ratio Radar performance
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