tailieunhanh - BOOK DOPPLER RADAR OBSERVATIONS – WEATHER RADAR, WIND PROFILER, IONOSPHERIC RADAR, AND OTHER ADVANCED APPLICATIONS_ part 2

Over the last decades Doppler radar systems have been instrumental to improve our understanding and monitoring capabilities of phenomena and processes taking place in the low, middle, and upper atmosphere. Weather radars, wind profilers, and incoherent and coherent scatter radars implementing Doppler techniques are now used routinely both in research and operational applications by scientists and practitioners. This book brings together a collection of essays by international leading authors devoted to different applications of ground based Doppler radars | Part 4 Weather Radar Quality Control and Related Applications 12 Quality Control Algorithms Applied on Weather Radar Reflectivity Data Jan Szturc Katarzyna Osródka and Anna Jurczyk Institute of Meteorology and Water Management - National Research Institute Poland 1. Introduction Quality related issues are becoming more and more often one of the main research fields nowadays. This trend affects weather radar data as well. Radar-derived precipitation data are burdened with a number of errors from different sources meteorological and technical . Due to the complexity of radar measurement and processing it is practically impossible to eliminate these errors completely or at least to evaluate each error separately Villarini Krajewski 2010 . On the other hand precise information about the data reliability is important for the end user. The estimation of radar data quality even as global quantity for single radar provides very useful and important information . Peura et al. 2006 . However for some applications such as flash flood prediction more detailed quality information is expected by hydrologists Sharif et al. 2004 Vivoni et al. 2007 Collier 2009 . A quality index approach for each radar pixel seems to be an appropriate way of quality characterization Michelson et al. 2005 Friedrich et al. 2006 Szturc et al. 2006 2008a 2011 . As a consequence a map of the quality index can be attached to the radar-based product. 2. Sources of radar data uncertainty There are numerous sources of errors that affect radar measurements of reflectivity volumes or surface precipitation which have been comprehensively discussed by many authors . Collier 1996 Meischner 2004 Sálek et al. 2004 Michelson et al. 2005 . Hardware sources of errors are related to electronics stability antenna accuracy and signal processing accuracy Gekat et al. 2004 . Other non-meteorological errors are results of electromagnetic interference with the sun and other microwave emitters attenuation due to a wet