The use of X-band polarimetric radar to assess the impact of severe convection in urban drainage system

Weather observations are conventionally performed by single-polarimetric scanning C-band weather radars with a temporal and spatial resolution of approximately 5 min and 1 km, respectively. However, for urbanized areas, these resolutions may not be sufficient to obtain accurate quantity precipitation estimation (QPE) of fast-evolving weather phenomena. Therefore, to model fast rainfall-runoff processes and related short response times, urban hydrological modelling requires high resolution rainfall input data. In this work, a dual-polarimetric X-band weather radar (IDRA) located in the Cabauw Experimental Site for Atmospheric Research (CESAR) observatory of the Netherlands (NL) is used to observe and derive physical processes and obtain accurate QPE of severe rainfall events at high temporal and spatial resolutions. A large convective front moving over Western Europe on January 03 2012 was observed using the two C-bands operational radar from The Royal Netherlands Meteorological Institute (KNMI in Dutch initials) and IDRA. The rainfall amount forecasted for the same event by the weather model HARMONIE (HIRLAM ALADIN Research on Mesoscale Operational NWP In Euromed) is used to study its implications at urban scales. The accuracy on estimated rainfall from HARMONIE and KNMI radars is compared against IDRA radar to analyze the spatial variability of QPE and its impact on the drainage system of Rotterdam urban area.