|Title||Comparison of OPERA precipitation radar composites to CMORPH, SYNOP and ECMWF model data.|
|Year of Publication||2008|
|Secondary Title||Technical Memorandum|
The Pilot Data Hub of the Operational Programme for the Exchange of weather RAdar information (OPERA) across Europe is operated by the Met Office in Exeter (UK) and produces 4-km resolution European composites of radar precipitation rates every 15 minutes. The aim of this study was to obtain a preliminary assessment of the quality of OPERA precipitation estimates, for the prospect of their use in model validation or even radar data assimilation. OPERA data have been compared to three independent precipitation datasets: CMORPH (satellite based), SYNOP rain gauges and short-range forecasts obtained with ECMWF's operational model. Statistics in the form of mean maps, time series and skill scores over various regions in Europe have been computed for two months in spring 2008 and for precipitation accumulations over 6 hours. OPERA precipitation rates exhibit systematic and consistent differences with respect to the three other datasets. These differences seem to be dependent on geographical location: OPERA tends to give less precipitation over most of Europe, except over France and the North Sea where a significant excess is found. Overall, the best agreement of OPERA with the other datasets is obtained over Germany, Belgium, the Netherlands, and to a lesser extent over France and Poland. Less satisfactory results are found over Scandinavia while a particularly unrealistic excess appears over the North Sea and a strong deficit is evidenced over the UK. The reasons for these latter departures could be clarified in the course of this study. The interpretation of other differences will require interaction with the OPERA community.