The Sensitivity of Single Polarization Weather Radar Beam Blockage Correction to Variability in the Vertical Refractivity Gradient

Abstract

Radars operating in complex orographic areas usually suffer from partial or total beam blockage by surrounding targets at their lowest elevation scans. The need for radar quantitative precipitation estimates in such environments led to the development of beam blockage corrections. This paper aims at evaluating the performance of beam blockage corrections under different electromagnetic propagation conditions with particular interest in anaprop situations. Three years of radiosonde data collected at Barcelona, Spain, a typical Mediterranean coastal site, are used to characterize the behavior of the vertical refractivity gradient near a weather radar. Three different targets surrounding the radar have been chosen and used to evaluate the different beam shielding simulated under different propagation conditions. A simple interception function between the radar beam and the topography is proposed and used for the different targets and propagation conditions considered. Results show that beam blockage correction is generally robust, with departures of 1 dB from the standard propagation conditions correction less than 10% of the time. However, as the presence of extreme anaprop cases would lead to higher differences, the monitoring of the propagation conditions is suggested as a criteria to be considered, among others such as the analysis of the echo structure, as a quality control of the radar quantitative precipitation estimate.

Quality Control Algorithms Applied on Weather Radar Reflectivity Data

“…For this purpose a degree of partial beam blocking (PBB) is computed from a digital terrain map (DTM). According to Bech et al (2003Bech et al ( , 2007, the PBB is calculated from the formula:…”

Effect of radar rainfall time resolution on the predictive capability of a distributed hydrologic model

“…The CAPPI are calculated by means of the IRIS program, which is based on the linear interpolation of the range to the selected heights in spherical coordinates, with a correction for the Earth curvature to preserve data quality. The radar imagery was corrected using SMC by first passing a filter to remove ground clutter (Bech et al, 2003). A second filter was applied to remove the interference between radars (no data in radar location) and from other non moving targets, such as a wind power plant.…”

Improving weather radar observations using pulse‐compression techniques

“…The observations were recorded on 29 June 2004 with the EXTOP03 CDV radar of the Doppler radar network of the Meteorological Service of Catalonia. Note that the radar coverage is largely influenced by a highly complex topographical environment that produces frequent clutter and substantial blockage in the area (Bech et al, 2003). simple 1 µs, simple 40 µs and NLFM (compressed) 40 µs.…”