FOR 2589:  Near-Realtime Quantitative Precipitation Estimation and Prediction (RealPEP)

• Subject Area: Geosciences
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 320397309

High-quality near-real time Quantitative Precipitation Estimation (QPE) and its prediction for the next hours (Quantitative Precipitation Nowcasting, QPN) is of high importance for many applications in meteorology, hydrology, agriculture, construction, water and sewer system management. Especially for the prediction of floods in small to meso-scale catchments and of intense precipitation over cities timely, the value of high-resolution, and high-quality QPE/QPN cannot be overrated. Polarimetric weather radars provide the undisputed core information for QPE/QPN due to their area-covering and high-resolution observations, which allow estimating precipitation intensity, hydrometeor types, and wind. Despite extensive investments in such weather radars, QPE is still based primarily on rain gauge measurements since more than 100 years and no operational flood forecasting system actually dares to employ radar observations for QPE. RealPEP will advance QPE/QPN to a stage, that it verifiably outperforms rain gauge observations when employed for flood predictions in small to medium-sized catchments. To this goal state-of-the¿art radar polarimetry will be sided with attenuation estimates from commercial microwave link networks for QPE improvement, and information on convection initiation and evolution from satellites and lightning counts from surface networks will be exploited to improve QPN. With increasing forecast horizons the predictive power of observation-based nowcasting quickly deteriorates and is outperformed by Numerical Weather Prediction (NWP) based on data assimilation, which fails, however, for the first hours due to the lead time required for model integration and spin-up. Thus, RealPEP will merge observation-based QPN with NWP towards seamless prediction in order to provide optimal forecasts from the time of observation to days ahead. Despite recent advances in simulating surface and sub-surface hydrology with distributed, physicsbased models, hydrologic components for operational flood prediction are still conceptual, need calibration, and are unable to objectively digest observational information on the state of the catchments. RealPEP will prove that in combination with advanced QPE/QPN physics-based hydrological models sided with assimilation of catchment state observations will outperform traditional flood forecasting in small to meso-scale catchments.

• DFG Programme: Research Units

Projects

• Assimilation of polarimetric information and observation-based nowcasted fields in numerical weather prediction (Applicants Potthast, Roland ;  Simmer, Clemens ;  Trömel, Ph.D., Silke )
• Coordination Funds (Applicant Trömel, Ph.D., Silke )
• Infrastructure project: Multi-Sensor Compositing for Hydrometeor Classification, High-Impact Weather, Nowcasting and Data Assimilation (Applicant Trömel, Ph.D., Silke )
• Large scale evaluation of QPE, QPN and QPF improvements in a flash flood nowcasting framework with data assimilation (Applicant Kollet, Stefan J. )
• Observation-based weather analysis and Nowcasting (QPN) (Applicants Carbajal Henken, Cintia ;  Simmer, Clemens ;  Trömel, Ph.D., Silke )
• Physics-based QPE using polarimetric radars and commercial microwave links (Applicants Chwala, Christian ;  Trömel, Ph.D., Silke )

• Spokesperson: Privatdozentin Dr. Silke Trömel, Ph.D.