Variation in bright band height during the passage of a typhoon observed with wind profiler radars

When snow particles fall and pass through the melting layer, they melt from the surface and change into rain particles. At this time, due to the difference in permittivity between ice and water, reflectivity appears large, and this is called the bright band (BB). Since the BB causes confusion in the precipitation estimation of weather radar, many studies on BB detection have been conducted to improve the quantitative precipitation estimation accuracy of weather radar and the performance of numerical models. Wind profiler radar (WPR) is useful for vertical structure analysis of mesoscale convective systems with excellent temporal and vertical spatial resolution. We analyzed the bright band of Typhoon HAISHEN passing near the Korean Peninsula from 00 UTC on September 06 to 00 UTC on September 07, 2020 by 9-site WPR. As the HAISHEN approached, distinct precipitation patterns and BB were detected with vertical signal to noise ratio and vertical radial velocity. The BB height gradually increased as the typhoon approached, and decreased as it moved away. Therefore, the precipitation converged in the front of the typhoon and originated from a stratiform structure. It is known that the BB height depends on local factors such as ground temperature and topography. However, the BB height in Jeju Island and Chupungnyeong, located on the mountain boundary at about 240 m above sea level, showed 3-4 km and 4-5 km, respectively. In order to understand the structure of a rapidly developing precipitation cell, it is necessary to investigate the dynamic parameters which are optimal to retrieve based on WPR.