Analysis of the Reflections of Dual-pol Radar Beam from Skyscrapers

During a strong squall line passing over west side of KLWX radar on 12 July 2020, two trains of moving echoes are found on east side of the radar. The echoes show weather-like returns despite the absent of storms in that area. A similar phenomenon persistently occurs in the KLWX radar observations when east-moving storms are present on the west side of the radar. Analysis of the terrain and landscape using Google Earth revealed several skyscrapers in the path of the moving echoes, with two of the buildings featuring plain surfaces facing the radar. As a result, these buildings not only partially blocked the radar beams, but also reflected them. A geometric study indicates the moving echoes on the east side were the reflection of squall line on the west side based on the locations of the buildings, KLWX radar, and the orientation of the building façade. We examined and compared the dual-pol and Doppler velocity measurements of the east reflected echoes with those at the corresponding locations on the west side and found them to be consistent. Because all the dual-pol variables were measured along the affected radials, it was possible to estimate radial profiles of rain rate using R(A). These results from reflected signals matched the rain rates at the corresponding locations quite well.