Correction of Reflectivity in the Presence of Partial Beam Blockage over a Mountainous Region Using X-Band Dual Polarization Radar

Abstract

Two approaches to correcting the partial beam blockage of radar reflectivity in mountainous areas were evaluated using X-band dual polarization radar data from the Hakone mountain region, Kanto, Japan. The comparatively simple digital elevation model (DEM) method calculates the power loss in the received signal based on the geometrical relationship between radar beams and a DEM. The second approach, the modified DEM method, attempts to account for unknown power losses related to ground clutter, hardware calibration errors, etc. Comparison between ground data and reflectivity data corrected by both methods suggests that the DEM method alone was insufficient to correct beam blockage problems but that the modified DEM data were in generally good agreement with the ground data. The authors also estimated 10-min rainfall amounts using reflectivity corrected by the modified DEM method and compared these with data from a network of rain gauges in the mountainous region. In general, the results show good agreement between radar estimates and rain gauge measurements. On the basis of their results, the authors conclude that the modified DEM method offers a suitable solution to the problem of beam blockage in mountainous regions, provided that the beam blockage rate is less than 80%.

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

“…et al, 2013). However, radar estimates of rainfall using Z H in areas of beam blockage are clearly biased in comparison with the ground-truth data (Zrnic and Ryzhkov 1996;Vivekanandan et al, 1999;Kucera et al, 2004;Krajewski et al, 2006;Friedrich et al, 2007;Lang et al, 2009;P.C. et al 2013).…”

“…Z H is a widely used parameter to estimate rainfall rate; many studies have used it to generate models that closely follow ground-truth data, especially for light to moderate rain Kim and Maki, 2012;P.C. et al, 2013).…”

“…Complex topography, which includes irregular features and high mountains, can shield the radar beam, affecting observations. Several methods have been developed to address this problem in mountainous regions (e.g., Vivekanandan et al, 1999;Dinku et al, 2002;Kucera et al, 2004;Krajewski et al, 2006;Friedrich et al, 2007;Lang et al, 2009;P.C. et al, 2013).…”

Intercomparison of attenuation correction algorithms for single-polarized X-band radars

“…A number of studies have shown that these high-resolution X-band weather radars can fill gaps in nationwide networks or be used for further investigating areas of special interest, e.g. mountainous regions (Beck and Bousquet, 2013;Shakti et al, 2013; Figuras i Ventura, J., Tabary P., 2013), urban areas (Berenguer et al, 2012;Chen and Chandrasekar, 2012;van de Beek, C. Z. et al, 2013), airports (Turso et al, 2009 or regions prone to floods (Matrosov et al, 2013).…”