Application of a modified digital elevation model method to correct radar reflectivity of X-band dual-polarization radars in mountainous regions

Abstract

This study focuses on the application of a modified digi- tal elevation model (DEM) method that not only considers geometrical power losses but also addresses effects such as power losses caused by ground-clutter filtering and the radar system’s calibration errors. X-band dual-polarization radars operated by the Ministry of Land, Infrastructure, Transport and Tourism of Japan are located near mountainous ter- rain in the southern part of the Kanto region in Japan, at Fujinomiya and Shizukita. Both radars suffer from problems caused by partial beam shielding at various low-elevation angles, which lead to underestimation of the amount of rain- fall. After correcting for reflectivity attenuation, a modified DEM method was applied to correct for bias reflectivity in the presence of beam-shielding problems. Validation of the corrected reflectivity based on comparison tests shows that the modified DEM method significantly improved the bias reflectivity caused by partial beam blocking.