The main objective of this paper is to evaluate, at the urban scale, the accuracy of the new French operational radar processing chain deployed within the French operational weather radar network. Such an evaluation is conducted by comparing radar data resulting from this processing chain (with a 1-km² resolution) to rain gauge data at four different time scales, i.e. 5,15, 30 and 60 min. These data are supplied by the Trappes Radar Station, located 30 km southwest of Paris. A total of 69 rain gauges installed within a radius of 80 km from the weather radar have provided the ground reference data. The dataset comprises 50 varied rainy days. The influence of distance, quality code of the radar data and type of rainfall, as well as the adjustment factor, is analyzed. The present analysis moreover seeks to evaluate the error specific to reference data by considering instrumental and representativeness errors, for the purpose of taking reference data accuracy into account in the radar/rain gauge comparison. This study shows that radar data obtained by means of this new operational radar processing chain are not yet reliable enough for direct use in quantitative applications within the field of urban hydrology.
