Advantages of using multiple Doppler radars with different wavelengths for three dimensional wind retrieval

Abstract. The Wind Synthesis System using Doppler Measurements (WISSDOM) is a practical scheme employed to derive high-resolution three-dimensional (3D) winds using any number of radars. This study evaluated the advantages of using multiple radars with different wavelengths in WISSDOM for the analysis of bow-shaped convection in a severe squall line recorded on 2 August 2020. A total of 11 radars were in operation in the areas surrounding Seoul metropolitan, South Korea: four S-band, two C-band, and five X-band radars. The advantages of using these radars were assessed using six different synthesis scenarios: (1) four S-band (scenario S), (2) two C-band (scenario C), (3) five X-band (scenario X), (4) a combination of four S- and two C-band (scenario SC), (5) four S- and five X-band (scenario SX), and (6) four S-, two C-, and five X-band radars (scenario SCX). The results revealed that scenario S offered good coverage in the synthesis domain, but relatively fewer observations were produced near the surface. In contrast, scenarios C and X provided sufficient data at lower levels but less coverage in the areas far from the radars. The scenarios SC and SX captured the return flow at low levels similar to typical squall line structures. Overall, the scenario SCX led to the optimal synthesis when compared with the observations. The mean bias (MB) of the U- and V-winds between the sounding observations and scenario SCX was 0.7 and 0.5 m s−1, respectively, while the root mean square difference (RMSD) of the U- and V-winds were around 1.7 m s−1. In addition, when comparing the retrieved WISSDOM winds with three radar wind profiler observations, the average MB (RMSD) for the U-, V-, and W-winds was 1.4, 2.0, and 1.0 m s−1 (3.1, 3.9, and 1.5 m s−1), respectively. The significant differences between scenarios S and SCX can be attributed to additional low-level observations in SCX, which allowed for the capture of stronger updrafts in the convection areas of the squall line. Overall, these results highlight the advantages of using radars with multiple wavelengths in WISSDOM, especially C- and X-band radars.