Simulation Study on the Accuracy of Modified Distributed Beamforming in Phased Array Weather Radars for Various Precipitation Events

This paper presents a simulation-based study on a modified distributed beamforming (DB) technique in phased array weather radars for operational accuracy. The technique uses electronic steering along with mechanical rotation for reducing the variance in the measurements as well as pulse compression to compensate for sensitivity reduction. The modified technique is used for estimation of polarimetric variables for stratiform and convective storms while the performance of this technique is compared with already existing DB techniques. The estimated polarimetric variables are impacted by the varying beamwidths of the transmitting as well as receiving beams as well as the sensitivity of the measurements. Thus, the modified DB technique performance evaluation has been done for variation in sensitivity, effective beamwidth, resolution and sidelobe level. For this study, measurements are simulated using radar variables from CSUCHIVO data taken during the Remote Sensing of Electrification, Lightning, and Mesoscale/Microscale Processes with Adaptive Ground Observations (RELAMPAGO) field campaign. The simulated measurements are used to estimate the radar variables for beamforming which in turn are used to determine accuracy and effectiveness. The modified DB technique radar variables have been found to have error less than 10 dBZ for reflectivity, 1 dB for differential reflectivity and 0.2 for correlation coefficient. In addition to that, the beamforming technique has been tested for reflectivity variation with signal to noise ratio (SNR). The modified DB technique is found to perform at par with the already existing DB methods while completing volumetric scan at a speed similar to mechanically rotated or even faster