International Symposium on Weather Radar and Hydrology (WRaH2008) location:Grenoble, France date:10-12 March 2008
In a research project of the Hydraulics Laboratory of the Katholieke Universiteit Leuven (K.U.Leuven) for the water company Aquafin, a small, short range, high resolution X-band weather radar called Local Area Weather Radar (LAWR, DHI) has been installed in the densely populated city centre of Leuven (Belgium). The radar beam has a horizontal opening angle of approximately 4 degrees, making quantitative precipitation estimation possible up to a distance of 15 km from the radar site. The radar data are being used to study the impact of the spatial variability of rainfall on sewer system design and operation.
Since weather radar measures the rain rate indirectly (through measurement of reflected energy), the system needs to be calibrated before quantitative precipitation estimation is possible. For this, data of a network existing of several well calibrated tipping bucket rain gauges are used. The calibration procedure of the rain gauges is based on the one described by Luyckx and Berlamont (2001), and consists of a dynamic calibration in the field, which takes the loss of water due to the tipping motion of the bucket explicitly into account.
In the radar calibration technique, the tipping bucket rain gauge errors are taken into account. It is assumed that these errors are mainly due to wind influences, the gauge resolution and errors in the gauge calibration. Errors in the near point (or small grid size) radar registrations are analyzed, and propagated to errors in the areal rainfall estimates.
Luyckx, G. and Berlamont, J. (2001). Simplified method to correct rainfall measurements from tipping bucket rain gauges. In: Proceedings of the 5th International Conference on Developments in Urban Drainage Modelling, Orlando, USA.