Comparison of the Observation Capability of an X-band Phased-array Radar with an X-band Doppler Radar and S-band Operational Radar

An X-band phased-array meteorological radar (XPAR) was developed in China and will be installed in an airplane to observe precipitation systems for research purposes. In order to examine the observational capability of the XPAR and to test the operating mode and calibration before installation in the airplane, a mobile X-band Doppler radar (XDR) and XPAR were installed at the same site to observe convective precipitation events. Nearby S-band operational radar (SA) data were also collected to examine the reflectivity bias of XPAR. An algorithm for quantitative analysis of reflectivity and velocity differences and radar sensitivity of XPAR is presented. The reflectivity and velocity biases of XPAR are examined with SA and XDR. Reflectivity sensitivities, the horizontal and vertical structures of reflectivity by the three radars are compared and analyzed. The results indicated that while the XPRA with different operating modes can capture the main characteristic of 3D structures of precipitation, and the averaged reflectivity differences between XPAR and XDR, and XDR and SA, were 0.4 dB and 6.6 dB on 13 July and -4.5 dB and 5.1 dB on 2 August 2012, respectively. The minimum observed reflectivities at a range of 50 km for XPAR, XDR and SA were about 15.4 dBZ, 13.5 dBZ and -3.5 dBZ, respectively. The bias of velocity between XPAR and XDR was negligible. This study provides a possible method for the quantitative comparison of the XPAR data, as well as the sensitivity of reflectivity, calibration, gain and bias introduced by pulse compression.