Comparative Study on Attenuation Correction schemes for X-Band Weather Radar Reflectivity Factor

In recent years, hundreds of X-band weather radars have been deployed in China. Vast amount of radar measurement data has been archived. However, these data suffered from precipitation attenuation due to the short wavelength of X-band. The attenuation evidence is obvious in the case of moderate to heavy precipitation, and the attenuation gets severe if the precipitation is intense, degrading the reliability of X-band radar measurement of reflectivity factor. Therefore, believable attenuation correction becomes necessary for the application of X-band weather radar measurement. KDP, one of polarimetric radar variables, is widely used to correct the attenuation by precipitation because it is immune to attenuation. The reliable scheme ZH-KDP and the innovative scheme k-LWP are used in the study for attenuation correct effect analyses, the sample data consists of 4 datasets collected by X-band weather radar during 2 storms, and the adjacent S-band radar data is used to evaluate the correction effects of the 2 schemes. The results indicate that: (1) Both schemes have good performance on attenuation correction, and k-LWP has advantage over ZH-KDP because of less possibility of over-correction. (2) ZH-KDP scheme is valid only on dual-polarization radar, but k-LWP scheme can work on both polarimetric and non-polarimetric radar with good practicality and robustness; (3) KDP is prone to be affected by non-Rayleigh scatters like ground object and hailstone, increasing the difficulty to get precise KDP. In contrast, LWP is hard to be affected by ground objects and hailstones, and calculation of k-LWP scheme is simpler. Case studies verify that the k-LWP scheme is highly effective for the attenuation correction of X-band radars.