The tradition of weather radar collaboration at the European level dates back to COST~72 (Measurement of precipitation by radar) which started in 1979 and which presented its final report in 1985. The results from COST~72 led to the launching of COST~73 (Weather Radar Networking; Newsome 1992) which ended in 1991. At that point, operationally-oriented activities continued in GORN (Liaison Group on Radar Networking) which, eight years later, led to the establishment of OPERA (Operational Program on the Exchange of Weather Radar Information) within the framework of EUMETNET (the Network of European Meteorological Services, www.eumetnet.eu.org). At that time, the clear objective was ``To harmonize and improve the operational exchange of weather radar information between National Meteorological Services''. The second phase of OPERA, 2004-2006, has involved a significant renewal of the Program's terms of reference, priorities, activities, and working methods (Huuskonen 2006).
I Holleman, L Delobbe, A Zgonc. Update on the European Weather Radar Network (OPERA)
2008, 0, WMO