Approaches to radar reflectivity bias correction to improve rainfall estimation in Korea

Abstract

Abstract. Three methods for determining the reflectivity bias of single polarization radar using dual polarization radar reflectivity and disdrometer data (i.e., the equidistance line, overlapping area, and disdrometer methods) are proposed and evaluated for two low-pressure rainfall events that occurred over the Korean Peninsula on 25 August 2014 and 8 September 2012. Single polarization radar reflectivity was underestimated by more than 12 and 7 dB in the two rain events, respectively. All methods improved the accuracy of rainfall estimation, except for one case where drop size distributions were not observed, as the precipitation system did not pass through the disdrometer location. The use of these bias correction methods reduced the RMSE by as much as 50 %. Overall, the most accurate rainfall estimates were obtained using the overlapping area method to correct radar reflectivity.

Improving CINRAD Radar QPE Through GPM‐DPR Reflectivity Bias Correction

“…You et al. (2016) noted that a GR in Korea has low biases of 7 and 12 dB for rain events on 8 September 2012 and 25 August 2014, respectively. Warren et al.…”

“…Since radar reflectivity correction is of universal need, various approaches have been presented, such as using floating metalized balls, disdrometers, well‐calibrated GRs, and so on (Atlas, 2002; Gourley et al., 2006, 2009; Lee & Zawadzki, 2006; Pedersen et al., 2010; Ryzhkov et al., 2005; You et al., 2016). Although the cost of metalized balls is low, the complicated operation process makes the method unsuitable for frequent use (Atlas, 2002).…”

Mitigating Spatial Discontinuity of Multi-Radar QPE Based on GPM/KuPR

“…Gourley et al [9] indicated that a discrepancy of 2-3 dB between reflectivities measured by adjacent WSR-88D radars was quite common, and that the inconsistency between radars would lead to spatial discontinuity for MGR-QPE. You et al [10] analyzed several ground radars in South Korea and found the largest difference of reflectivity was up to 12 dB. Xiao and Liu [11] reported that the difference of S-band operational radars in South China was around 3 dB.…”