Improving Hydrometeorological Forecasting Using High-Resolution X-Band Radars (HyFoX)

• Applicant: Katharina Lengfeld, Ph.D.
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management ; Atmospheric Science
• Term: from 2015 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 270422832

Europe has recently been affected by a number of heavy and long lasting rainfall events. Especially mountainous and urban regions are at high risk, because heavy rainfall induces devastating floods at steep slopes and in impermeable areas leading to serious damage. Forecasting these floods and their impact on flood-prone regions is still one of the biggest challenges for hydrometeorological forecasters. The largest source of error in flood forecasting is uncertainty in precipitation estimation. Precipitation fields from C-band radars with temporal resolution in the order of 5 min and spatial resolution in the order of kilometres, as operated by national weather services, are used as input for state of the art rainfall-runoff models. Novel polarimetric systems can derive products with spatial resolution of 250 m, but still temporal resolution of 5 min. Despite higher influence of attenuation by precipitation in the X-band frequency range, X-band radars and in particular networks of overlapping X-band radars have been proven to be a valid tool to provide precipitation fields for areas of special interest in higher temporal (< 1 min) and higher spatial resolution (< 250 m) in complementation to nationwide radar networks. Within the interdisciplinary project Improving Hydrometeorological Forecasting Using High-Resolution X-Band Radars (HyFoX) under supervision of Prof. Daniel Sempere-Torres at the Centre de Recerca Aplicada in Hidrometeorologia (UPC-CRAHI), Barcelona, Spain, three different regions will be investigated: Rural flat area in the North of Hamburg, Germany; flat urban area of Hamburg, Germany, and mountainous urban area of the Besós River catchment including parts of Barcelona, Spain. All three catchments are covered by C-band radar networks operated by the corresponding national weather services and by X-band radars operated by the University of Hamburg and UPC-CRAHI. For each catchment rainfall-runoff models are available and in use. This unique set-up allows for a detailed innovative study of the impact of high-resolution precipitation fields on rainfall-runoff modelling. The hydrological simulations will be validated by comparing the results to water level and stream measurements. All data and models needed for HyFoX are available and ready to use, but have not been combined yet. The aim of HyFoX is to demonstrate the impact of high-resolution weather radar observations on runoff simulations in comparison to and in complementation of polarimetric C-band radars in different environments. The results will be valuable for identifying flood-prone areas of increased risk more precisely. This is highly relevant, especially in urban areas, where floods cause damages running into billions. Advice can be given for which areas setting up single or networks of low-cost, high-resolution weather radars as a complementation to larger scale networks is beneficial for improving flood forecasting and enhancing prevention and risk management.

• DFG Programme: Research Fellowships
• International Connection: Spain
• Host: Professor Dr. Daniel Sempere-Torres