Comparison of ODYSSEY precipitation composites to SYNOP rain gauges and ECMWF model

TitleComparison of ODYSSEY precipitation composites to SYNOP rain gauges and ECMWF model
Publication TypeMiscellaneous
Year of Publication2014
AuthorLopez, P
Secondary TitleTechnical Memorandum
Number717
Abstract

A systematic comparison of ODYSSEY European precipitation composites with both synoptic station rain gauge observations and ECMWF short-range forecasts was carried out over the period March 2012 to October 2013. Statistics indicate that the agreement between ODYSSEY and the two other datasets has been substantially improving over Western Europe during this period, while some issues remain especially over Eastern European countries and over mountainous regions. Indeed, interferences with other microwave sources are still present, even in recent composites, which leads to an obvious degradation of quality over these regions. Furthermore, large systematic positive biases over southeastern Europe would also suggest that S-band radars are not handled as well as C-band radars in the compositing process. Persistent contamination from ground-clutter echoes also appeared in spring 2013 for several weeks over the Netherlands, leading to a dramatic degradation of the agreement between ODYSSEY and the two other datasets. Lastly, the inadequacy of ODYSSEY's current Z-R relationship in snowfall situations causes a systematic large underestimation of precipitation in the wintertime over colder regions. Ongoing efforts by the OPERA community to improve the quality and homogeneity of precipitation composites are strongly supported by ECMWF because the assimilation of radar data on the European scale might be beneficial to operational global numerical prediction, as it is already the case with NCEP Stage IV composites over the United States.