Meteorol Atmos Phys 101, 159–173 (2008) DOI 10.1007/s00703-007-0266-3 Printed in The Netherlands Radar Centre, Institute of Meteorology and Water Management, Katowice, Poland Research studies on improvement in real-time estimation of radar-based precipitation in Poland A. Jurczyk, K. Os ´ro ´dka, J. Szturc With 12 Figures Received 10 April 2006; Accepted 22 March 2007 Published online: 30 July 2007 # Springer-Verlag 2007 Summary Precipitation estimation plays a key role in meteorological and hydrological forecast systems. In Poland during last years a lot of effort has been put to improve quality of radar-based precipitation estimation. In this paper, the following particular tasks are described: (1) radar pre- cipitation accumulation taking account of spatial and tem- poral interpolation, (2) spatial interpolation of raingauge data (using inverse distance weighting method or Kriging), (3) combination of raingauge observations and radar es- timates (based on Sinclair-Pegram technique), and (4) downscaling of coarse resolution precipitation fields to required high resolution. All the research studies were performed considering operational needs and requirements. 1. Introduction After the most disastrous flood in Poland in 1997 which inundated over 5000 km 2 , Insti- tute of Meteorology and Water Management (IMWM) has been developing Hydrological and Meteorological Monitoring, Forecasting and Pro- tection System. In the frame of the system the modern measurement and processing networks have been established: weather radar network called POLRAD, station for satellite data receiv- ing, meteorological and hydrological telemet- ric networks, system NIMROD for precipitation nowcasting, COSMO-LM numerical weather pre- diction model, and complex System of Hydrol- ogy IMWM. This comprehensive system is running in real- time mode. However for fully effective use the system needs some research studies on particular algorithms in order to improve their performance and implement newer ideas and solutions. Partic- ipation in the RISK-AWARE project (‘‘Risk advanced weather forecast system to advise on risk events and management’’) in the frame of INTERREG IIIB CADSES programme gives the opportunity for more intensive works on these subjects. The study is undertaken to investigate how to get the best estimates of precipitation field for hydrological use. It provides information about concepts and solutions worked out during the works on improvement in radar precipitation es- timation. Described algorithms are focused on: accumulation of radar data (Chap. 3), spatial in- terpolation of raingauge data (Chap. 4), radar and raingauge data merging (Chap. 5), and down- scaling of coarse nowcast precipitation fields (Chap. 6). Correspondence: Anna Jurczyk, Institute of Meteorology and Water Management, Radar Centre, 40-045 Katowice, Poland (E-mail: anna.jurczyk@imgw.pl)