Correcting rain gauge measurements for calibration of an X-band weather radar

In an ongoing research project of the Hydraulics Laboratory of the Katholieke Universiteit Leuven for the Flemish water company Aquafin, a compact, short range high resolution Xband weather radar has been installed in the city centre of Leuven (Belgium). The radar beam’s horizontal opening angle of 3.9 degrees makes quantitative precipitation estimation possible up to a distance of 15 km. The radar data will serve as input to a sewer network model to study the impact of the spatial variability of rainfall on model results, and hence on sewer system design and operation. Because weather radars measure rain rate indirectly – by measuring reflected energy – the system requires calibration to enable quantitative precipitation estimation. For this calibration, data of a tipping bucket rain gauge (TBR) network will be used. Since it seems reasonable to assume that the accuracy of the ground level measurements will affect the resulting radar calibration to some extent, the TBRs are corrected for local wind-shelter rain losses as well as losses due to the tipping bucket mechanism. This paper describes the followed procedure to enhance TBR data accuracy. The second phase of the study will focus on the effects of this enhancement on final radar performance.status: publishe